Hello everyone, my 2001 5.4 is having trouble starting. Its like theres bad gas but im not sure. Let me run down the list alright.

Last day i drove it was Saturday and it ran fine all day and i probably drove over 250 miles but it was o.k. Well Sunday afternoon when i went to crank it its like it did not want to fire. Well it normaly idels at 6 or 700 rpm's and today when i tried to crank it studderd and finnaly fired but very weak and it's ideling at 1000 rpm's and when i accerlate in park it revs but when the rpms drop it shakes and vibrates the whole truck. right now i tried and its ideling at 1200 rpm's and is vibrating bad. What could this be.

 

Sounds like your IAC's stuck.

No engine light ?

Tap on your IAC with the handle part of a screw driver while it's running - if you can. Use a broom stick - that works too beleive it or not lol.

Yeah , try that , see if your Idle straightens out. If that's the case , it just needs to be cleaned or replaced.

 

If it's running that bad, you have a CEL? Get the codes and go from there.

 

I agree with jbrew, sounds too familiar to me. You can remove, bieng careful with the bolts and gasket, clean with t-body cleaner good and see if things get better. If it does, just bare in mind you'll need to replace it sooner or later because you'll be cleaning this time every year. Clean the t-body while your at 'er, never hurts. It's seasonal maintenance.

 

(this pick if from a 2001 5.4L)

See that little red line connected to the Thottle body? Behind the throttle body , you can see part or your IAC in this pic - it's pointing upward back by the firewall.

 

It's that valve inside that gets dirty and sticks when it does..

 

Sounds like the IAC is stuck. If it's really screwed up, eventually it'll turn the check engine light on and/or store codes in continous memory, usually P1506 or P1507. You can beat on it with a broom handle or something to get it going, and cleaning may fix it temporarily, but the ultimate fix is to replace it.

 

Hi Quintin lol

 

Heres a slightly better pic...

 

You may also want to check into the fuel pressure regulator. I had a similar problem on my last truck (99 Silverado). Would crank and crank and crank and then fire up but sound like it wanted to die. Eventually it would be fine. It was because the FPR had reptured and was dumping fuel directly into the vacuum line into the intake and flooding the engine with fuel. The part cost all of $50 to replace and after replacing it it was perfect. Just a thought.