truck running rough...again!

[eric huskey 2]

My truck has started running rough again. I thought I had fixed it but the demon has come back! It has a hard miss at idle and lacks power and sputters when I take off. It also misses when under a load going up a hill. At crusing speed and if I punch it to pass it runs fine. I previously changed plug wires. Took out and inspected all spark plugs. Cleaned maf and iac sensors. Checked the fuel pressure.Allof these things did nothing until I run seafoam through the intake and I put fuel injection cleaner in the gas tank. It fixed it for 2 months. This problem happens after it gets up to temperature then it doesn't go away. Also my truck is a 01' job1.

 

[Rodger Tellefson]

Cleaned maf and iac sensors.

Did you do the IAC motor cleaning project? You need to pull it off and clean it with carb cleaner. You may need a new IAC motor.

 

[eric huskey 2]

I did take off and clean the IAC. It went bad about 2 yrs ago and I replaced it. When it did go bad the truck wouldn't start. But it could be bad again Roger.

 

[eric huskey 2]

Previously when this happened before it thew a P0171 code. I found 2 collapsed hoses that went to the pcv valve. I replaced them but still had the rough idle until I did the seafoam.

 

[eric huskey 2]

Is there a way to test the IAC to see if it is good or bad?

 

[Rodger Tellefson]

First I want to point out the use of the Edit Button.

Is there a way to test the IAC to see if it is good or bad?

I personally am not aware of how to test the IAC, but Todd Z or Fast Eddie'04 might be able to answer that question.

 

[EddieS'04]

Here is an article on how to test the IAC. It is a job 1 motor. It will be the same.

 

[Matthew Runals]

Could it be the throttle body?

 

[Kevin Palmer]

Did you check the fuel pressure when the engine was up to temp AND under a load?



Almost sounds like a plugged filter or a weak fuel pump to me.

 

[scott degroot]

Actually sounds like you have an injector dropping out to me. If you had access to a decent scanner and someone that actually knows what they are doing you could access mode 6 data and look at the misfire test results to determine what cylinder is being affected so you have a starting point as opposed to playing this guessing game. Being that you have a miss under load you can automatically rule out the Iac and the throttle body, they just simply won't cause the problem you are having.

 

[Evan F]

Usually the coil when under load or hot causes this. Check the coil.

 

[Gavin Allan]

Do you have a cam in it? My buddy's camaro runs rough, and he said it is because he put a cam in it. :banana: