Engine hesitates and sluggish acceleration

Tiny
MRDETROIT
  • MEMBER
  • 2001 FORD F-150
  • V8
  • 2WD
  • MANUAL
  • 47,000 MILES
A recent problem is a lack of power at acceleration. It hesitates and "bucks" from start and from a roll. I have to shift down to 2nd or 3rd to maintain any speed when climbing a hill. But there is no check engine light displayed. I had a more pronounced occurrence approximately 2 years ago, but with check engine light. The code disclosed the coil over on #7. Replacement of same resolved issue.
Friday, July 18th, 2008 AT 9:28 AM

60 Replies

Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
Its common when one coil out the rest tent to follow here is are diagrams below of the job being done so you can fix yours with a guide that should help as well.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Check out the diagrams (Below). Please let us know what happens.
Images (Click to make bigger)
Thumb
Thumb
Was this
answer
helpful?
Yes
No
-1
Saturday, July 19th, 2008 AT 6:04 AM
Tiny
RICKY RANCOUR
  • MEMBER
  • 1 POST
  • 2000 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 187,000 MILES
How is it going? So my truck has recently started to idle really bad to where it might stall but does not. It also loses power when trying to accelerate. I have need to my local parts store and they suggested cleaning my throttle body and EGR valve and idle air control which I performed this weekend to no avail. Any thoughts?
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,648 POSTS
Hello,

I would start with a tune up and then check the engine for vacuum leaks, here are a couple of guides that will shoe you how to get the problem fixed.

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

and

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please let us know what you find ;)

Cheers, Ken

Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
PACKERS27
  • MEMBER
  • 205 POSTS
  • 2000 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
I do not have any codes shown. All coils and packs are brand new. I have a cold air intake with a Spectre air filter. New fuel filter. My mechanic ran an inspection camera down the exhausts and did not find any restrictions. He said that the converters were actually gutted.

Truck runs good but as you go up any incline, I have to hit the accelerator or I will lose speed. When I hit the accelerator, I will get up to 3,000 rpm's until the climb is made then it goes back down to normal. It is like the motor should not be trying so hard. From stop to fast take off, it is all exhaust. No squealing tires or anything like that. It could use some faster improvement from 0 to 50. What are some things that can make this better? Is there an easy way to find exhaust leaks or a product that can indicate a leak? Thanks!
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,648 POSTS
Exhaust leaks will cause low power a smoke machine or visual inspection should help with that but to me it sounds like you have low fuel pressure. Here is a guide to help us check the pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Fuel Pressure
Key on, engine off .................... 240-310 kPa (35-45 psi)
Engine running .................... 193-345 kPa (28-50 psi)

This guide can help as well

https://www.2carpros.com/articles/engine-has-low-power-output

Please run down this guide and report back.

Cheers, Ken
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
NICKBAR87
  • MEMBER
  • 30 POSTS
  • 1999 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 219,000 MILES
Every time I attempt to take off from a standstill I have no power to accelerate. Engine has no problems/trouble codes. Transmission has no issues, fluids have been changed, along with electrical issues that occurred due to a wiring issue. What could be the cause of no acceleration power at take off?
Was this
answer
helpful?
Yes
No
+1
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,648 POSTS
Hello,

This sounds like a classic plugged catalytic converter here is a guide to confirm the issue.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Please let us know what happens.

Cheers, Ken
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
NICKBAR87
  • MEMBER
  • 30 POSTS
I removed all cats, I have better throttle response now. But when actually taking for a drive it doesn't seem to want to shift gears.
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,648 POSTS
I have seen where the MAF sensor can be a little off and cause low power and give false information to the PCM causing late shifts. Have you installed a new one recently? This sensor should be replaced as a regular maintenance item. When this sensor gets off a little it will not trigger a trouble code.

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

It also sound like a input shaft sensor can be causing problems as well but those will trigger a code when they go out.

Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
NICKBAR87
  • MEMBER
  • 30 POSTS
I have a maf code and haven't changed it recently. But no codes for the input shaft
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,648 POSTS
The MAF can cause the problem. That is what I would try next.
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
NICKBAR87
  • MEMBER
  • 30 POSTS
Yea, I just don't want to start throwing money at it though, bc the maf sensor for my truck is $100
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,648 POSTS
Yep the sensor can be off a little which can be detected by a scanner that can read live data, and then compare that reading to a known good sensor. Some scanners have both live and average readings for a normal sensor. That is the only way to test you currant sensor that I know of.
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
RED FORD
  • MEMBER
  • 2 POSTS
  • 1998 FORD F-150
  • 185,000 MILES
When I accelerate the truck acts like its not getting enough fuel. It idles and revs fine in park and nuetral. Takes a couple cranks to start(twice as much as normal). Awhile ago I changed the fuel filter for the first time since ive owned it, bought it at 177k. The truck ran great right after I changed it. It ran like my dads new 4.6l ford. The next day the truck ran the same way it previously did(before the filter change). I proceeded to change the fuel tank, fuel pump, and fuel filter again. No change has occurred. The truck is still running bad. No idea what to do from here.

Also the the mpgs are low about 7mpg
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Check the actual pressure. check the back pressure for the cat converters as well. Please go over these guides to help find the issue.

https://www.2carpros.com/articles/engine-has-low-power-output

and

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Please run down these guides and report back.

roy
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
RED FORD
  • MEMBER
  • 2 POSTS
Thank you for your reply. I'm working on getting a fuel pressure gauge. How do I go about checking the back pressure for the cats? The exhaust is dual with separate mufflers. Both outlets seem to have a good steady pulse, when checked by hand.
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
You remove upstream o2 sensor and insert a fitting which measures the back pressure

Roy
Was this
answer
helpful?
Yes
No
+1
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
JIMMY1719
  • MEMBER
  • 2 POSTS
  • 1998 FORD F-150
  • 40,000 MILES
When I accelerate it stays at the same speed and does not advance I changed the coil module thinking it was that but it wasn't. If its the fuel pump what do I do and how much would it cost? It shakes when I accelerate I don't know what it can be?
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
You can change the pump yourself and save a bundle by removing the tank. check this link, our site made a great article about it.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

this is not the same car but gives you an idea :-)
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)
Tiny
JIMMY1719
  • MEMBER
  • 2 POSTS
OMG that was such good info! This site rocks :-)
Was this
answer
helpful?
Yes
No
Tuesday, June 29th, 2021 AT 9:05 AM (Merged)

Please login or register to post a reply.

Related Engine Low Power Content

Fix an Engine with Low Power!
VIDEO
Fix an Engine with Low Power!
In­struc­tional re­pair video
Symptoms of Low Engine Power
GUIDE
Symptoms of Low Engine Power
The power your car's en­gine is pro­duc­ing is im­por­tant. When you step on the gas you need your car to ac­cel­er­ate, mainly to keep you out of trou­ble when get­ting onto the...
VIEW MORE