Could be, but I think this went off the rail after original post. Was it acting up at idle or while driving? IAC only effects idle. If while driving, it could be TPS.

Check fuel pressure. Should be 45-50.

 

So you went from knowing very little to replacing the plenum gasket in a months time. Awesome job and congrats on tearing into it and learning how to do stuff on your own. Have you cleaned the throttle body as suggested? How many miles are on the truck? Did the last tune up include all the mentioned items?

 

5 bucks says this is the plenum gasket

 

well i didnt do it. my brother-in-law who is a mechanic and body man did it. i didnt want to get into a lengthy message. im not exactly sure if he cleaned the throttle body, but i do know he replaced the plenum gasket, coil pack, and a pvc valve. tune up wasnt done that long ago (mile wise). its got almost 130k miles on it. the problem is that the check engine light isnt coming on. but intermittently it runs like crap. almost like its either not getting enough air, or not enough fuel. when the light came on, i went to an auto parts store to see what the problem could be, and the light wasnt on, and hasnt came back on since. would a bad fuel pump/filter cause the light to come on? tired of putting money at problem that might fix it, but definitely cant afford a new(er) tuck payment. people i talked to said with out the engine light on a computer wont help. but like i said, anything past doing an oil change and putting gas in it, i need help.

 

Fuel pump in and of itself won't set a code, and turn on the lite. Some of the symptoms of low fuel pressure would though, mainly, engine always running lean, since the PCM can't spray enough fuel.

Also, various sensors can be bad, but, not necessarily set a code. Crank sensors are notorious for that. Cam sensors can do the same, but, not as common.

Best bet is to look for common factors of just WHEN it does it. Engine temp, outside temp, how much fuel is in the tank, etc. Look for a pattern.

 

thats the thing. there is no pattern. i do not let my truck get below half tank of gas. temps anywhere from warm to really cold. when it acts up is usually when im driving at a constant speed (regardless of mph). i let off the gas, doesnt do it. when it does acts up, i floor it, and it stops. knock on wood, it hasnt died, or left me stranded, but i dont like my truck running like crap for an unknown reason. i dont treat it badly. i dont go off-roading (very rarely anyway) and dont pull/haul things that are to heavy. its perplexing to say the least.

 

How old are your O2 sensors?

 

Hard for us to help if you cannot/will not answer the questions asked. What is the fuel pressure??????

 

never seen the question asked gdstock. plus i have no idea what my fuel pressure is.