Hi ive spent countless hours researching and wrenching. The truck just doesn't like to start after sitting 1-2.5 hours. fuel pressure is at 32 when running. 40 psi with fpr vac line off.

ive cleaned intake, checked egr for functionality and changed injectors

any help would be awesome

 

Check all vacuum lines and spark plug coil pack crank sensor fuel filter battery take your time troubleshoot these guys on here will help I am too new working on a 1997 Ford F 150 5 .4 liter 4x4 extended cab it is a work in progress fixing issues from previous owners

 

You may need to take the throttlbody of clean throttle positioning sensor and so forth they do have a tendency to get plugged up

 

Would help if you provided more details. Engine, year, miles. Is it a cold start issue or only after sitting 1 to 2 hours. Overnight starts ok? Normal tune up stuff new or relatively new: plugs, air filter, fuel filter? Cranks fast enough?

Gas engines need fuel, air, spark, exhaust. I have fixed poor warm start from bad coil(s), plug wires, fuel filter, EGR, worn timing chain, etc.

 

I take it U haven't a code ? U probably have intake manifold issues.

 

thanks for the replies guys.

the problem occurred every once in a while in the summer and now frequent.

I have changed the pcv valve, injectors, cleaned intake and throttle body, checked egr for function (sucked on vacuum line and it stalled) sprayed out iac and looked for leaks. a few weeks ago it spit a spark plug and since has been fixed with a thread kit. it has thrown a po300 multiple misfire code twice now. it went out on its own the second time. I deleted it the first time.

things im thinking about replacing: fuel pressure regulator, clean maf, spark plugs. when it sits for a few hours and wont start warm, I checked fuel pressure and it was at 20 psi, cranked a few times and it went to 40 psi like normal and it cranked then sputtered to life. Yet, it has done the starting problem under normal fuel pressure conditions.

Maybe not fuel related? it drives very well when running, no hesitation when throttled up.

 

I was going to help , screw that if he can't even post what he has lol.

 

I am sorry just didnt realize i left that out.

its a 2000 5.4 with 125,000 miles. I bought off PO last year and done regular maintenance. I cleaned the intake 3 times since summer. so its not clogged up. appears to have no vacuum leak anywhere either.

help would be appreciated

 

Probably the IAC. What's your warm idle at in park?

It cranks/turns over no problem right?

 

park or neutral its around 900. in gear its about 600.

it idles smooth but sometimes when cold started it stumbles.

Isn't IAC only for cold starts? it starts right up on cold starts or just running in/out of store.