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Question:
2003 Pontiac Grand AM mileage: 29,000. After filling
the tank recently the engine speed became erratic: it
would race while driving (tach at 1800 forcing me to
keep my foot on the brake in a 25 mph zone); when
braking for a turn it would vary wildly between a couple
hundred and 1500 rpm; if breaking quickly rpm would fall
to under 400, would sputter and stall unless I would
two-foot. It continued to do this intermittently,
sometimes stalling while cornering. I took it to the
dealer for its 60,000 mile scheduled maintenance; they
found no problem except a possibly partially clogged
fuel injector. I used some OTC fuel injector cleaning
stuff to no avail. Took it to a very good independent
mechanic. He spent three days checking sensors, motors,
valves, computer, draining and replacing the fuel.
Everything independently checked out A-OK. He's
mystified. What do I do now?
Answer:
Your car is
equipped with a electronic throttle control. So there is
no adjustment. The idle speed is determined from the ECM. You need to scan your car for trouble
codes. A oxygen sensor or Mass Air Flow has probably
shorted and needs replacing.
Question:
2002 Toyota Camry mileage: 70,000. The car has a rough
idle when in "drive" (auto trans, A/C off). In Neutral,
it is barely noticeable. While driving, it is fine.
Only when I come to a stop does it shake. It had a
major tune-up (cap, rotor, wires, plugs, filters,
timing, etc.), injectors were cleaned - no difference.
The dealer is at a loss and so am I! HELP!
Answer:
Your car
is equipped with a electronic throttle control. So there
is no adjustment. The idle speed is determined from the ECM. You need to scan your car for trouble
codes. A oxygen sensor or Mass Air Flow has probably
shorted and needs replacing.
Question:
1990 Chevrolet Corsica mileage: 177,000. Recently
had to replace both throttle position sensor and air
idle control valve. The car never seemed to reset
its idle. 2 weeks later am having same problems as before. What
could be causing the TPS and/or AIC to fault? I realize
a bad TPS will destroy the AIC's. I am assuming that is
what is happening. Air, electric, and fuel systems are
all showing to be code free.Answer:
Replacing the oxygen sensor should fix your problem.
Question: 1999 Chevy
Impala mileage: 127,000. I have taken my
car to three different mechanics to have this
problem solved and have yet to get it lined out. It has
extreme hesitation on the throttle, and when the car
slows from normal driving speed to a stop it dies. The
idle does run rough whereas before this problem occurred
it purred like a kitten. I've replaced the computer,
map sensor, throttle position sensor, starter relay, and
according to the Chevy Dealer they are not getting any
new readouts of problems. I'm running out of options on
this problem. I'm hoping you may have an idea of what
to do.
Answer:
Check the
EGR valve to make sure it is closed at idle.
Inspect the engine for vacuum leaks and check the
exhaust system and
catalytic converter to see that they
are not plugged.
Question:
1998 Ford F-150 4 WD mileage: 114,000. My truck
problem is ROUGH IDLE, POOR GAS MILAGE, HESITATION,
after a short drive (10 miles) or so, if I shut the
engine off and restart, the motor is hard to start and
about 1 mile down the road the check engine light comes
on. I took my truck to several mechanics and have
replaced the THROTTLE POSITION SENSOR, 02 SENSOR, WATER
TEMP SENSOR, They got me an Emissions sticker but the
problem still remains. I recently used the truck's
self-diagnostic tester and the following results (codes)
were obtained. KOEA: 31-EVP circuits below minimal
voltage. KOEA: 32-EVP voltage below closed limit. KOEA:
33-EGR valve not opening. KOEA: 41-O2 sensor not
switching. RUN CODE: 21-No idea what this one means!
RUN CODE: 44-Secondary air inoperative. RUN CODE:
33-EGR valve not opening. I'm just an idiot trying to
follow a Haynes manual, and not sure where to go from
here, and need some advice! Please Help- the cost of
gas is killing me! Thanks for the help!
Answer:
Reset the computer, then turn the key on to see if any
immediate codes are present, if so then repair as
primary codes warrant. If nothing comes up start engine
and recheck system. what we are testing for in this
problem is to only repair the most prevalent coeds as it
can create the other secondary codes. Then check the fuel injector
resistance to be sure one is not shorted. Check
fuel pump pressure and fuel
pressure regulator.
Question:
2000 Isuzu Pickup 4x4 mileage: 46,000. It is in
great shape. Recently when slowing down for a stop, push
clutch in and idle speed picks up and then goes down 3
times before becoming stable. Sometimes goes from 800
rpm to 1500 rpm. Have replaced plugs, filters,
wires, O�, and scanned computer with no error codes.
Cleaned throttle body. Checked for vacuum leaks.
Posted this on a newsgroup and at least 4 other people
have had the same problem. Suspect a sensor, but not
sure how to tell.
Answer: Check the EGR valve to see that it
is closed at idle. Check for a vacuum leak in the power
brake booster. Check for a plugged catalytic
converter. Check for leaking fuel injectors.
Question:
1999 Honda Civic mileage: 60,000. Recently the
idle has become very sporadic. As soon as you start the
car the idle will jump from 700 rpms to about 3500 rpms
it will hold and then go back down it does this over and
over, it will do this whether the car is hot or cold.
What is causing this? Please help!
Answer:
Your car
is equipped with a electronic throttle control. So there
is no adjustment. The idle speed is determined from the ECM. You need to scan your car for trouble
codes. A oxygen sensor or Mass Air Flow has probably
shorted and needs replacing.
Question:
1999 Chevrolet Lumina mileage: 106,500. Vehicle runs
fine down the highway, but after exiting and idling, it
"misses" and at times smells rich. Replaced TPC and gas
filter. Some improvement. While engine was running
rough performed an adjustment to the EGR (i.e. tapped it
slightly with a wrench) and problem cleared up.
Vehicle ran fine for 2 weeks and now the same is
happening. Again, tapped on EGR and problem seems to be
corrected. Should EGR be replaced or can it be
cleaned/repaired? Also, could the oxygen senor be part
of the problem?
Answer:
It is probably time to replace
the
EGR valve. If a major tune-up has not been done
recently, this could be the cause of your problem.
Replace the spark plugs, plug wires, fuel and air
filters, etc. Also, replace the oxygen sensor. In
addition, service the fuel injection system. Clean the
carbon deposits from the throttle bore and idle
passages.
Question:
2003 Ford Explorer mileage: 42,000. My car misses
and idles very roughly. The idle will drop down
suddenly from about 900 rpm to 400-600 rpm then pops
back up again. It has had degrees of this symptom for
a few thousand miles, possibly dating back to when the
battery failed and had to be replaced. A dealer
tune-up and a couple bottles of gas treatment have not
made things any better.
Answer:
Your car
is equipped with a electronic throttle control. So there
is no adjustment. The idle speed is determined from the ECM. You need to scan your car for trouble
codes. A oxygen sensor or Mass Air Flow has probably
shorted and needs replacing.
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