oldtruck

Two things to check one the pvc hose have been known to get soft and split open and when they get warm they get sucked closed (vacumn leak gone warm engine) the second thing is intake gaskets that seal up when the engine is hot.Try having someone try to keep it running when cold while you spray water from a window cleaner bottle and see if things change when you spray around the intake gaskets.I use water because it will not burn if it hits the exhaust or a spark from the wires

Ace_Savant

Thanks for replying, I have replaced the PVC hose and valve, no luck. I tried the water spray and could not find a difference. I've had 2 or 3 mechanics look at it now and they are all stumped. They say I have good manifold vacuum, and everything else seems to check out.

rallye26

I apologize guys for not coming back into my own thread. I had it subscibed to send an email if there were new posts and it never did until now.

My issue ended up being a bad MAP sensor. I had no CELs and it seemed to check out fine when I tested it. The shop I took it too ended up having a spare one sitting there since they had the issue before on a couple of thier old company trucks. They plugged it in to try it and it ran like a champ. Don't know why it never threw a CEL or why it still tested okay, but it worked. Might be best to try one from someone you know. I ended up paying 180 for this one from them as it was a genuine motorcraft part. I found some cheaper aftermarket ones but the shop I took it to said they'd been there many times and those cheapy ones don't last. Might have been just trying to sell me theirs, but Im willing to spend a little extra to have the motorcraft part.

Ace_Savant

Well, I replaced the MAP sensor, and to my incredible dismay, it didn't change anything. I'm running out of things to replace, and yes I know its stupid of me to pour money into it without knowing the problem, but I'm truly down to guesswork at this point. Any more suggestions from anyone?

Frank g

Hi guys, I have the same problem as the first guy on here. I noticed my check engine light came on the other day and today I started my truck right up, it idled around ~600rpms but then died, unless I give it some gas and then it will idle fine after a few minutes of my foot on the gas. It even died today at a stop sign, and when I start to go when it's in drive, it is like it won't catch at first and it will start to shake real bad until I get up to 25mph. Thanks for Any help you guys can offer!

88 ford f150 5.0L EFI automatic 75,000miles

bbaccama88

i have a 94 bronco and mine is doing the same thing ive replaved the fuel filter and pump (mine kicked the bucket) and it still was doing it so i asked one of the guys at my job whos a big ford guy he told me to try my engine coolant temp sensor because i was running a high idle to start and running rich then it would go to the low sputtering idle i havent tried it yet im going to on friday but maybe that might help its only a 20 dollar part so it cant hurt

Boss Man

Try replacing the crankshaft sensor

Steve83

Try replying in LESS THAN 9 YEARS.

JohnPaul Escobar

Did you ever figure out this problem? My 89 f150 5.0 is doing the exact same thing.

JohnPaul Escobar

Did you ever figure this problem out? My truck is doing the exact same thing and I'm stumped.