Free Automotive Repair Advice by Certified ASE Technicians
Repair Topics / Vehicle
Has Loss of Power-1 / Vehicle Has Loss of Power-2 / Vehicle Has Loss of Power-3
Vehicle Has Loss of Power Hesitating
Engine has low output (power)
Today's engines have been designed to have more output power and lower
emissions then ever before. So when the output of your vehicles engine is
compromised it is easily detected. When your vehicle has low power output it can
mean several different things are occurring. What you should know is while your
car has low performance it could be damaging your vehicle the longer you operate
it. Example: The emergency brake is on and you did not notice, this condition
will burn up the rear brake pads or shoes and cause premature brake failure. Or,
the fuel filter is clogged and the fuel pump is laboring and causes premature
pump failure.
Several conditions can cause low power, one of the most popular is the fuel filter is clogged
not allowing the proper amount of fuel pressure and volume into the fuel
injection system. Next, the exhaust system is clogged not allowing exhaust
gasses to exit the system properly. Most exhaust clogging problems are caused by
the catalectic converter, but we have seen a muffler or two cause problems. The fuel system could be lean or severely rich causing improper fuel combustion.
Next, the spark timing could be maladjusted, but most vehicles today have crank
trigger systems, (no adjustment required). And the air filter could be plugged
causing low air intake not letting the engine breath properly. Plus the fuel
pump could be faltering providing low system fuel pressure, low fuel, low
power. If the
engine is worn out, when engines exceed there life expectancy the compression is
compromised (low compression) causing low power output.
Common problems
1. plugged fuel filter causing low fuel pressure in the fuel injection
system.
2. plugged air filter not allowing the proper amount of air into the engine.
3. fuel pump is worn providing low fuel pressure to the fuel injectors.
Visit -
How to
Tune Up your engine
This
category contains featured questions as
examples. They relate to most vehicles.
Question: 2001 GMC 3500
mileage: 138,000. I am having a pinging
problem while driving down the highway at 55
to 60 mph, flat road, also when I put my
foot into it to pass, sometimes. Also when
starting out whether the engine is warm or
cold driving back on the freeway it's as if
there is lack of power, sputtering as if it
just doesn't want to go and then after a
minute it will start to speed up fine. This
is an intermittent problem as it doesn't
always happen. Have taken it to the dealer
twice. First time they changed the fuel
pressure regulator. Engine has never set a
code so they are also at a loss. Sometimes
it does it sometimes not. The engine seemed
to work for a few hours after they changed
the fuel regulator, but on a trip the
problem returned again. Have tried different
levels of octane fuel, changed fuel filters,
air filter is fine. When it starts to ping
it will do it when the engine reads cool or
warm, I just climbed through Mt. Shasta and
had no problem with pinging, though
sometimes when I tried to pass it once again
seemed to lack power and then just take off
and run fine. I'm at a loss and the dealer
has no ideas. Any suggestions on what I
could trouble shoot to solve this. Dealers
answer has been to drive it till it gets
worse, which will probably happen when I'm
on a trip. Thanks for any help.
Answer: It sounds like a fuel
pump is starting to fail. It is common for
fuel pumps to fail at the mileage your truck
has on it. Replace fuel pump and fuel
strainer (attached to the bottom of the fuel
pump) with new to repair problem.
Question:
2002 Dodge 1500 Ram Truck mileage: 72,000. I have
recently replaced all of the oxygen sensors, fuel pump,
fuel filter and fuel regulator and the car still has no
acceleration power on the highway. I need to know
if it is some I can do it myself I live in Fargo, ND. I
look forward to hearing from you. Thank you in
advance for your time and your cooperation.
Answer:
Your lack of acceleration is probably caused by a
partially plugged catalytic converter. Remove to
inspect, replace as needed to recheck system.
Question:
2002 Chevrolet Suburban mileage: 110,000. One day I
stopped my suburban and went inside. A couple of hours
later, I went back outside to leave, and it wouldn't
start. So, I looked around for the source of the problem
and I found that it wasn't getting any fuel. I found out
the fuel pump wasn't working, it just went out. So I
changed the fuel pump. After that I started it up and it
idled just fine. But if I would rev it up it seemed to
get bogged down and backfire. So I checked the sensors,
and I also hooked up a code scanner to it, it said there
was a problem with the O2 sensors. So I changed them,
that was $180. That didn’t solve my problem. So I did
some tests on the pollution devices and different
sensors, but they all checked out. So, I called a
mechanic he said it may be the fuel pressure regulator
and fuel filter, so I changed that, and that didn’t fix
it. I was hoping you could possibly give me some ideas
on it.
Answer:
If the fuel pump you installed was not OEM original
equipment manufacture, that is the problem. The fuel
pressure it takes to run you vehicle depends on 60 psi
fuel pressure constant. Inexpensive fuel pumps are that
way for a reason, there are not as good and cannot hold
pressure. Replace fuel pump with OEM fuel pump to repair
problem.
Follow up from Steve:
Also cheaper fuel pumps don't last half as long, even if
they do run. Take that from me, with the family in the
car on the way to Nevada and we are stuck in a gas
station. The fuel pump that I just installed had failed.
So much for the LIFETIME WARRANTY ~@@**%$, It doesn't
help much when your car is broke down.
Question:
2003 Toyota 4 Runner mileage 85,000. I noticed that the
truck had lost some power, I had the timing belt done
back at the recommended 70K. Anyway it pulls strong, but
seems to have some very minor break down on the top
end...perhaps about 4500 rpm or so. It is faint but as I
build and race cars (Camaros) I notice it. You can hear
the motor rev and it does accelerate but not as strong
as it should...almost sounds as if it is bogging a
little, but seems to be more of a breaking down (loss of
spark) than anything else. I am thinking it is coil
related? The truck has three coil packs one fires one
plug on one bank as well as the other on the other bank.
The truck is completely drivable, does not have any
skips or misses, however seems to have some break down
as mentioned. Any thoughts are greatly appreciated...I
drive the car pretty easy but noticed the problem when
goosing it onto the highway. The car does not pull any
codes.
Answer:
It sounds like its time for a tune up, spark plugs, air
filter, fuel filter service fuel injection system,
recheck system.
Question: 2002 Pontiac Grand
Am (quad 4) Mileage: 58,000. My mechanic is a
professional auto tech and he has had my car for 2 weeks
now. He has checked all sensors, the computer, the
ignition coils, the catalytic converter, and can't
figure out what is wrong. The car starts but misses and
only goes to about 10-12 mph with backfiring and a
burning smell. I believe it is the ignition coils
because two of the spark plugs are not firing; any
insight would be appreciated.
Answer: Replace
the ignition coil housing as they have a tendency to
short out on this model.
Question: 2002 Mazda Protege
mileage: 89,000. When driving home from work, I noticed
lack of power. Then, after stopping at a light, my rpms
dropped dramatically, and at acceleration, the car
jumped and jerked until I got to approximately 20-30
mph. At the next light, it stalled. I replaced the
plugs, and the fuel filter. I know it sounds like the
fuel injectors, but in Park, it idles fine. Is this
normal? Also, in Reverse, it seems to run fine as well.
People have told me it might be the transmission, but I
doubt this because the way the tachometer bounces like
that.
Answer: Check the rubber
intake boot that connects the fuel injection body to the
intake manifold. It connects to the Mass Air Flow Sensor
If it has a crack or tear, it must be replaced.
Question: 2002 Chevrolet Cavalier
mileage: 80,000. If you like a good mystery you'll enjoy
this question. My Cavalier drives along smoothly at 55
mph on level ground but as soon as I start to take it up
a hill it cuts back to around 35 mph. I can even get a
running start at 65 mph, but the car does the same
thing, it bogs down on the uphill incline. The following
things have been tested or replaced all to no effect.
The engine compression is good, the vacuum is good, and
spark is good. A diagnostic machine shows everything is
in good order. I have replaced the fuel filter,
catalytic converter, muffler, the map sensor and also
the idle air control valve. I changed the transmission
filter and replaced the fluid. I replaced the air
filter. I check the egr valve to assure that it was
functioning properly. The computer has been replaced and
that didn't help the problem either. Please help before
the guys in white coats come to take me away!
Answer: It sounds like a fuel pump is
starting to fail. It is common for fuel pumps to fail at
the mileage your car has on it. Replace fuel pump and
fuel strainer (attached to the bottom of the fuel pump)
with new to repair problem.
Question: 2000 Ford Ranger
super cab mileage: 147,470. I have been driving this
truck for quite some time now. Up until recently, I have
never had a problem with power or acceleration. Even
though this truck has a lot of miles on it, it always
had plenty of get up and go. Now it stutters, and almost
refuses to go up hill, no matter the grade. If the hill
is too steep, I have to keep it in second, and go 25. I
just replaced the spark plugs, wires, distributor cap,
gas filter, oxygen sensor, gas tank fuel line, oil
filter, and heater coil. So far, none of these
replacements have helped, but they were needed. Any idea
what might be wrong?
Answer: It sounds like a fuel pump is
starting to fail. It is common for fuel pumps to fail at
the mileage your car has on it. Replace fuel pump and
fuel strainer (attached to the bottom of the fuel pump)
with new to repair problem.
Question: 2002 Volkswagen
Jetta mileage: 45,000. Since purchasing the vehicle in
June 2002, I have never really been pleased with its
performance. It always felt more 'sluggish' than I had
expected. In March of this year, we had a new catalytic
converter fitted, which improved the speed/power of the
car for a period of 2-3 weeks. It was like driving a new
car...Gradually the power and the performance of the
engine deteriorated to the point where we now find
ourselves with a concentrated problem @ 2-2,500 revs.
(The best way to describe the problem is like a judder -
almost as if the car is thinking about what it has got
to do for a second!). It has also been described as a
lean stumble, hesitation...etc. etc. The car has had new
plugs, HT leads, ECU, Throttle switch, Air Mass Meter,
Full service and has been back to the Ford Dealer where
we purchased the vehicle. And to an Independent Engine
Management Specialist! We are at the point that as far
as we are being advised every possible component has
been checked / changed. We have even put Silicon Grease
on the plugs/lead at someone recommendation. Have you
got any ideas? I am pulling my hair out. Everybody I
speak has got a different opinion. Thanks Tracey
Answer: It sounds like a fuel pump is
starting to fail. It is common for fuel pumps to fail at
the mileage your car has on it. Replace fuel pump and
fuel strainer (attached to the bottom of the fuel pump)
with new to repair problem.
Question: 2002 Toyota Tundra
mileage: 76,000. Problems started at about 65,000 miles.
The truck loses power, acts like it is not getting fuel.
Replaced oxygen sensor, fuel filter, and did tune up.
Helped but still did not get rid of the problem.
Computer says the right side oxygen sensor is running
rich. Checked the EGR valve and it seems to be operating
correctly. What could the problem be?
Answer: This is difficult
because the computer can't detect the right problem,
your car thinks everything is ok. In reality what is
happening is the electrical component inside the MAF
sensor becomes contaminated by the impurities in the air
(heavies) These containments imbed themselves to
electrical component that senses the air flow causing
the sensor to be slightly off, but not enough to trigger
the MIL (malfunction indicator lamp). Replace the MAF
sensor with a new sensor and you're problem will go
away, plus your car get better mileage and performance.
(Mass Air Flow MAF sensor or Air Intake Sensor AIS,
depending on manufacture. It does the same thing with
different names).
Question: 1998 Mazda Miata
mileage: 60,000. The car had a new oxygen sensor
installed at 50,000 miles. The check engine light came
on after that and the repair shop said everything was
fine. After I disconnected the battery to work on the
radio (and reconnected it), the engine experienced major
power loss and hesitation, but the check engine light
went out. The readings from the O2 sensor and Mass Air
Flow sensor are within spec, but if I unplug the MAP
sensor, the engine runs much better (although not
perfect). I suspect that the MAP is bad and that the
computer was supplying a default value until
disconnected the battery and now that value is gone. I
think that replacing the MAP will solve the problem but
I'm looking for some assurance that I'm on the right
track before I lay out $190 from the dealer. Thanks
Answer: From what you tell us,
it would appear that the MAP sensor (manifold absolute
pressure) is causing your problems. Replacing it should
fix your problem. You can find that same part on
eAutoPartStore.com for about $104.99
Question: 2001 Chevrolet 1500
mileage: 73,000. I have changed the plugs, wires,
throttle sensor and EGR valve. I also changed the oxygen
sensor and had the catalytic converter checked. The
problem is that the truck loses a lot of power when
going up a hill and especially when I run the air
conditioner. Could something else need to be changed? No
codes have turned up on the computer since the EGR code
and it was changed. Thanks!
Answer: It sounds like a fuel pump is
starting to fail. It is common for fuel pumps to fail at
the mileage your car has on it. Replace fuel pump and
fuel strainer (attached to the bottom of the fuel pump)
with new to repair problem.
Question:
1999 Honda Accord mileage: 119,000. The car is a
Honda Accord with Manual transmission. The problem
is that when I accelerate with the pedal about One
quarter on the way down to full throttle it will start
to hesitate. Now this hesitation is like one
of the cylinders is not firing. Which could be
possibly true. But this does not happen all of the
time. Which is becoming irritating.
Sometimes it could do it when you startup and then for a
while it wont do it. I have replaced the spark
plus and wires. Have checked the fuel injectors
with an ohm meter and they checked out o.k.
Because all of them have the same reading.
This is the weirdest thing that my dad has come a
crossed too. He has been a mechanic for about
twenty years. I have heard that it could be an EGR
Valve problem, but I think I checked it out right and IT
was fine. Another thing we checked was distributor
cap and the rotor. I don't know what else this
could be. If you could be of any help, it would be
great. Thank You
Answer: Your problem sounds like a faulty
distributor. Replace ignition distributor with new to
recheck system.
Question:
2003 Mercedes Benz, CLK 500 Coupe
mileage:
42,000. Engine runs wonderfully, and get awesome
gas mileage (25-30 mpg), however, when accelerating, the
car will cut out for a few seconds, then suddenly take
off very fast, all the while my foot is holding the gas
in the same position. The transmission and fuel filter
replaced about 20k miles ago.
Answer:
Check the fuel pump pressure and the fuel pressure
regulator. Replace failed parts with new recheck system.
Question:
1999 Ford E150 mileage: 107,000. The vehicle lacks
power, especially when it is cold. It also has to
downshift to maintain a set 65 mph with cruise on.
This has gradually occurred over about 3 months. I
ran a self-test scanner on it, the response was code 225
"Knock sensor signal not detected". I am not sure
what that means. I recently put cap, rotor, plugs,
and wires on the van but this did not help. Thanks for
any advice, Mark
Answer: Try replacing the fuel filter
with new. Then check fuel system pressure. The knock
sensor code although active could not effect the
performance to that extent. The knock sensor is a
problem but not thee problem.
Question:
2002 Chevrolet 1500 Z71 4x4 mileage: 80,000. It was
running rough very little power. Found low fuel
pressure, so I replaced the fuel pump. Now it runs
great for approximately 5 minuets and quits. The
engine turns over but doesn't start. It will not
restart until I wait approx. 30 minuets. Then it
starts, goes for a while then quits again. What is up
with that.
Answer:
If the fuel pump you installed was not OEM original
equipment manufacture, that is the problem. The fuel
pressure it takes to run you vehicle depends on 60 psi
fuel pressure constant. Inexpensive fuel pumps are that
way for a reason, there are not as good and cannot hold
pressure. Replace fuel pump with OEM fuel pump to repair
problem.
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Has Loss of Power-1 / Vehicle Has Loss of Power-2 / Vehicle Has Loss of Power-3
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