Is there's mechanic in the house???

[jwh0818]

I have a 92 f150 efi 2wd half ton with a 4.9L inline 6. It has an auto tranny. Here is the problem. One day it started shutting off when you give it gas. No one can tell me what's wrong with it. I tryed the tps, icm, map, and the iac. Replaced the fuel filter and nothing works. It doesn't have a check engine light so I'm stumped

[barberking12]

did u check the fuel filter relay

[Nickintex]

Ask Eklikewhoa

[jwh0818]

I dont think this truck has a relay but where would it be if it does

[barberking12]

under the hood in the relay box

[Cesar]

sounds like maybe an airmass unit, it will mix the air to fuel mixture. Sound also lack power on acceleration, poor shifting bogging on acceleration things like that, hammer on it several times and I am pretty sure you will have a CEL light. If not its a bad throttle body, take it off and try cleaning it. Also try doing a fuel induction service to clean the fuel system.

[eklikewhoa]

I'm with C-note... to make an educated guess based on the symptoms air/fuel metering is a good bet. TPS would be the second thing to look at but a CEL is the first to be pulled to see what has failed or given a fault code.

[SunnyHouTX]

Did that model still have a vacuum line system? If it did, maybe a vacuum leak somewhere?

[jwh0818]

Okay I tried the tps and it didn't work. I have no clue what a CEL is and it has very good vacuum. I CAN put it in drive and slowly go and then floor it a couple time and it goes but still shuts off when you stop and then go. I also have removed the whole throttle body and cleaned it very well and it still doesn't work

[jwh0818]

Nevermind. Check engine light. The light doesn't come on at all when it shuts off. This truck has OBD 1 and I can't find anyone with it

[eklikewhoa]

Think by '92 they switched over to mass air and no longer ran speed density.
CEL check engine light.

There's a lot of things that could have gone wrong whether a simple problem or major, hard to tell by just guessing and not properly diagnosing the vehicle.

Some simple things to look at though...
Spark plugs/gap
rotor/cap
EGR vacuum lines
EGR opening/closing
"Coffee can" vacuum lines
Fuel Pressure

[jwh0818]

Okay I can tell you that the canister doesn't work. The vacuum lines bypass the can to give the egr the corect vacuum. If it was miss firing, wouldn't it run rough? And it doesn't run rough. That would mean its not anything to do with spark and vacuum. Right? Also would the fuel pump slowly start going out because it does shut off only in gear when you give it gas

[eklikewhoa]

Nevermind. Check engine light. The light doesn't come on at all when it shuts off. This truck has OBD 1 and I can't find anyone with it

With an OBD vehicle you can still pull codes through the CEL flashes, it will flash a series of codes when triggered. I forget how but it should be online. There are OBD readers that read backwards for the Non OBDII vehicles.

[eklikewhoa]

Okay I can tell you that the canister doesn't work. The vacuum lines bypass the can to give the egr the corect vacuum. If it was miss firing, wouldn't it run rough? And it doesn't run rough. That would mean its not anything to do with spark and vacuum. Right? Also would the fuel pump slowly start going out because it does shut off only in gear when you give it gas

burnt out plugs would cause a stumble in some cases.
Vacuum could also be causing the symptoms as well.

Again, it's hard to guess what it is without checking the truck, can only give answers based on past experience.

[jwh0818]

Do you have a shop somewhere? Or somewhere were you can look at it? No one can tell me what it is and God forbid auto zone. They couldn't tell you how to start a car