i am having a problem with my 1987 tbi 5.7l . every single morning the truck will run for about 2 or 3 minutes then stall. it doesnt matter if it is idling or driving. it only does it in the morning so far. after it stalls i am able to start it back up and it will run fine. i have asked a lot of mechanics about this and everything they have told me to do i have and hasn't changed anything. i changed the tbi gasket, the ignition module/cap/rotor, the temp sensor, esc module, has a new egr valve. i could not find any vacuum leaks. i tested the fuel pressure it was 12.5 psi



also.. i don't know if this is connected to the same problem but it did start at the same time, that is when the truck is running say doing down the highway, if i go above 3000rpm and let go of the gas and let it idle down, when it hit 2000rpm until 1200rpm the engine seems to surge, i can hear a loud sucking sound coming from the tbi. engine runs fine other wise, no power loss. no codes coming up.

truck has headers with a heated o2 sensor, and a open air cleaner,msd box and coil

the only thing i can think of now is to change the 02 sensor but i dont think it would help coz the truck runs fine after i restart it.

also another problem but not a big deal right now, just annoying is that when going down the highway to check engine light comes on and i get a code 32 for the egr, the egr is new i change the module as well. i don't understand why is always comes on?

anyone have any ideas that could help me out?
thank you from your time

 

Im having a similar issue somewhat. How did you check the fuel pressure? I'm thinking maybe the fuel pump could be going out, so it could be getting tired and heating up, causing it to shut down. Only things that come to mind are, IAC valve and fuel pump.

I would also replace the fuel filter... could be clogged as well.

 

If youd like, you can go check out my recent thread, had almost the same problem and now my car doesnt start period lol... I dont know much but just my 2cents, I would watch the injectors and see if they are slowly running out of fuel when it starts to stall.

 

Does it start right up after it stalls?
Keep the fuel press gauge on it, tape to the windshield.
I also like to hook up a timing light to it, put up on the cowl so you can see the flash or not if it stalls.
Its possible the mds is giving you problems too.
How does the ignition pick up coil look? I've seen some that look really rough & corroded that still run.
Check the grounds around the t-stat housing.

 

fule pressure is at 12.5 psi, the fuel fiter is good, the injectors seem to be spraying a nice cone shape. and yes it starts right back up after if stalls. i will check the pick up coil. but what i dont understand is the truck runs perfect after i restart it. and it only dies in the morning,so far. i start it in the morning and it dies after 2 minutes, then restart it and then its fine. until the next morning. any problem with the fuel pump or something else i would think it would cause problems all the time, like sluggish performance. its hard to diagnose cause its only doing it in the morning. :S

 

maybe a poor working coolant temperature sensor tricking the computer into the wrong temperature so then the computer is compensating wrong.

 

i changed that already, didnt make a differance

 

The sender, or sensor?
Sender = usually next to thermostat on intake.
Sensor/Switch = ? Coolant jacket on the side of block/head somewhere.

 

the sensor i believe, on the intake manifold next to the thermostat housing, what is the sender?

 

I might have the terms backwards(fixed above)...but anyhow the part im referring to is the one that actually tells your computer what temp your coolant is to make adjustments. That is located on the block/cyl head on the side somewhere. The one next to the thermostat housing just gives your gauge the reading, which does not affect your a:f ratio.

 

i think you are wrong, the sensor for the computer is on the intake, the 1 on the head is for the gauge, thats what the haynes manual says

 

It's possible that I'm wrong, but it's possible the book is wrong too. Guess you should unplug one and find out...

 

turns out it was the msd box, must have something wrong with it, after i unpluged it the problem seemed to go away, thanks for all your guys help.