Stalling, no start

[FirstFord]

Someone please help me out im going nuts, i've been having problems with my 94 x since i got it. It stalls at stop lights and after starting it, while warm usually. And after it stalls it wont start or will run for a few seconds, really ruff and die again, allready been to a mechanic, and said it was the egr vale tube, he said he changed this but this obviously wasnt the prob., I am convinced the truck needs a good tune up, but my mechanic says no.

 

[Opera House]

One difficult problem to detect

is a bad fuel pressure regulator. Mine would sometimes stall at stoplights and after trying everything else bought a new one. Cut the old one open and found a bevel worn on just one side of the seat because the spring wasn't centered. Under high vacuum conditions like idle and coming to a stop, the regulator opens the widest. It would slide over on this bevel and stick open. Other times the pressures were normal so a pressure test won't detect this until it happens. About $80 when your mechanic has tried everything else. This problem had everyone stumped.

 

[TPLYNCH]

Did he replace the DPFE while he was replacing the tubes??? Usually it's the DPFE that goes bad, as well as the tubes getting gunked up.

 

[FirstFord]

no, he didnt change anything else. I just did a tune up today, the plugs were shot, i also put in a K&N, and will clean the mass air sensor tommarow. So far the X has a lot more pickup, and all around better performance, one thing to i am having a problem with pinging, usually run 89 but today threw in 93, still can hear slightly.

 

[TPLYNCH]

Pinging is usually caused by dirty MAS and/or carbon buildup. Unless you have a chip, don't run anything but 87 octane.

 

[Rhett]

Running the 89 or 93 will make the pinging problem worse over time unless you've got a chip programmed for the high octane gas.

As was said, if you don't have a chip, the higher octane gas will burn incompletely, and this will increase the rate of carbon buildup in the combustion chambers.

I would do all of the things suggested by 100's of people on this site to end the pinging in this order, such as
1) clean the MAF sensor
2) check for vacuum leaks in the air intake system
3) use Sea Foam (best) or AMSOIL Power Foam (ok) to clean the manifolds and combustion chambers.
4) use Chevron Techron (good) or AMSOIL PI (good) about once every 6 months on a tank of gas
5) ensure the O2 sensors (you have 2) are working ok
6) ensure the FPR (fuel pressure regulator) is working ok
7) ensure the EGR system and PCV valve are operating
8) re-torque the lower intake manifold bolts

and others I probably can't remember, search on all of the above topics...

 

[FirstFord]

thank you all for your input, your replys were very helpfull.