To start i bought this truck about two weeks agao since then i've yanked the egr and put in a tomco clean screen
then i yanked the upper plenum and noticed the nut kit was leaking and the fpr was real bad had a puddle on the passenger side.

when i first bought the truck the gentlemen told me he thought and was told by numerous people tho check the cap
becasue it was driving ok until he had a new cap and plugs put in.

well upon the very first diagnosis the main vac line coming off the back (inches away from cap) was split in half so we replaced and check alot more with issues and fixed them! cant find anymore broken vac lines in the engine compartment i have yet to follow the ones going over top of my tranny and back to the fuel tank. im also grabbing a vac gauge today to see if this is the issue!

but after the nut kit and fpr im kinda at a loss? i really thought this was the issue? it still lopes for about a minute and stalls out in neutral and def stalls out in drive whether im stopping or not!

i read this could be the sensors on the plenum? (i forget all the initials) im wondering if the cap could have been put on wrong?
it also hesitates while driving at 40mph any other speed it is mostly smooth?

im all out of ideas? Any help would be a fantabulous


http://www.techsupportforum.com/auto...-problems.html
(i was also directed here by a friendly fellow from another forum here is the post with a little bit more detail)

 

I see that you have cleaned the EGR, but as was asked in the thread you linked to above, did you clean the pintle area of the EGR valve. It is possible that a chunk of carbon is holding the pintle open, causing your idle problem.

An easy way to find vacuum leaks is with an unlit propane torch. Trace along all intake gasket surfaces and vacuum lines with the unlit torch and the engine running. If the engine speed increases, then you have found a leak.

Also, you may want to remove and clean the idle air control (IAC) valve. It is located near the throttle body (if you can call it that) on the upper half of the intake plenum. That valve controls the air that is allowed into the engine at idle. If it is stuck, you could experience these same symptoms.

At this point, I do not know if the two problems (idle and hesitation) are linked to the same cause. Try the stuff above and let us know how it goes. We will work from there.

 

just tried the vac test you recomended.. nothing happened
i also got under it and found the three lines going back to i think the transfer case
right on the front side of the driveshaft?
anyways one of those lines has vacum the other two dont?
are they supposed to?


and the iac was checked prior to the cpi work. it was actually really clean even though it was never replaced!


also below the iac/throttle body there is a vac line i pulled it off under the air box and it didnt have vacum at all
so i pulled it offright below the iac and ran the engine and that didnt have any vacum unless iturned the throttle

also the EGR i made sure it was really clean.

 

I was also told that this could be the camlobesbeing worn down?

but wouldn't that create problems the whole time? it drives good except when its at idle then it stalls

im at a loss dont know what else to check except thethe cap being put on wrong? testing that this weekend

 

update i just hooked up the vac gauge i had 20 off the ball looking thingy and when i went to uplug the vac line coming off the back off the plenum it ran ok???

im assuming this is becasue i have a pinched line somewhere unless one of those line goes to my evap canisterbut i could have sworn the line off the front of the plenum under the thorttle went to the evap canister?? could it be one of the lines going back to the transfer case? and would that be causing the problem of it sputtering while driving at constant speed?


anyone have any ideas!!!???

 

So you removed the IAC valve and cleaned it? Sounds like you have an idle speed problem since it idles better with a large scale vacuum leak. You may need a new IAC valve.

 

I was thinking that, there was something wrong when i pulled the iac off it was spic and span which seemed odd to me?

but it also wouldnt move but im not even sure if its supposed to?

 

They'll move, but they require some force to get them going. The fact that a vacuum leak makes it idle better tells me that the IAC isn't doing its job.

 

Thank you so much!

ill give it a try im going to check to see if i can test it with volt meter first if not ill just replace it!

let ya know how it works out for me!

 

Update!

i just put the newIAC in didnt change anything?? i really thought that was it!I put it in started it up and it ran alittle better for a couple seconds then went back to its usual self? so i went and returned it

gonna get under it today and see if one of those lines going back above the tranny are piched along the way?