94 explorer sputters and tries to stall when stopped

[Relvie]

Hi guys I was wondering if anyone might be able to help with a problem I'm having. I have a 94 explorer 4.0 4x4 it runs and drives great except when its hot outside and I start to slow down for redlights.. ect. it ill drop rpm's almost to the point of stalling. No matter how much I press the gas or put it in neutral and try to rev it up it just continues sputtering often times completly stalling. I have to turn it off and restart it to get it to stop.

I've replaced the fuel pump and filter, MAF sensor,tps sensor, iac valve, checked and fixed any vaccum leaks, seafoamed it, run constant injector cleaner, I've taken all of the intake manifold and fuel injectors off and cleaned it all. Gutted the cats. New plugs and wires. New voltage regulator and both coolant sensors.

I'm still getting the same sputtering and stalls only when I slow down. When its up to speed it runs great. Also it seems to not do it when its cooler outside. On hot days its sputtering within 15 minutes of driving. I have tried researching this problem and cannot seem to figure it out. Anyone have any ideas?? Any help would be greatly appreciated. Thanks. -Mark

 

[Fastest Caskets]

I assume all the parts you changed are brand new? Some times used parts will give you the same symptoms....

 

[Relvie]

Yes all new. Just checked the plugs again and they are getting black already. Dipstick for the oil smells lightly of gas. Guessing its the fuel pressure regulater now. No gas coming from the vac line.

 

[Fastest Caskets]

give it a shot, if it's running rich, that could be the culprit. sounds like youve gone through everything else. I'm sure if you do a search you can find a method of troubleshooting the pressure regulator without just putting new one on. no fuel coming from the vaccume tube shows the diapragm isnt torn, doesnt mean the regualtor hasnt failed in another sense. good luck

 

[Relvie]

I'm gonna go ahead and replace it and see what happens. Ill let you know. Thanks for your advice.

 

[MrShorty]

Your symptoms sound a lot like mine with a bad fuel pump (new pump). the pump would overheat in hot weather and cut out.

Diagnosis started with a proper fuel pressure test (which can also be used to test the regulator).

 

[Relvie]

Your symptoms sound a lot like mine with a bad fuel pump (new pump). the pump would overheat in hot weather and cut out.

Diagnosis started with a proper fuel pressure test (which can also be used to test the regulator).

Gonna start with a fuel pressure test in the morning. Was yours running rich?

 

[MrShorty]

No. when the pump would cut out, the pressure would drop to 10-20 psi, which would cause the engine to run lean.

Apparently I missed post #3 where you stated that it appeared to be running rich. I'd still check fuel pressure, because you could have a situation where fuel pressure is too high for some reason, causing it to run rich.

 

[Relvie]

Checked my engine codes this morning.

41,53,63,66

Says that it ran lean, tps low signal, tps too high,maf low signal

Anyone know what might be going on?

 

[Jason94sport]

If it's not the Fuel regulator or pump, it may be a bad ECU. While not a common failure it has been popping up lately. These are old trucks.

 

[MrShorty]

This is on a '94? Any chance someone has put a '91 computer in it? '92 and later should be outputting 3 digit codes, not 2 digit codes. Not necessarily saying they are wrong, but that they are "unusual" and I want to make sure you've read them correctly.

That said, if the PCM is seeing a constant lean signal from the O2 sensor, and other symptoms are indicating that the engine is running rich, that suggests a fault in the O2 sensor or circuit.

 

[FLwireman]

About three years back my '93 EB would lope while decellerating from 45 or 55 mph. This went on for about a week, then it started loping when slowing down and when I stopped it would die. I could start it right back up and go okay. Then one hot afternoon it said "I ain't playing with you anymore" and would not restart. At that time the truck belonged to my boss, he had it repaired at a shop. Turned out to be the Computer. I think they found it by parts changing troubleshooting, because with labor it cost $411 and took two weeks. It was a used computer they put in and it is working fine. There are no pull-a-part junk yards here, all the meth heads sell everything for scrap metal.
Good luck with yours.

 

[Relvie]

I checked it 3 times to make sure. With the engine on it just flashed 111

 

[Relvie]

Cleared the codes and drove it around last night. Now I'm only getting "41" system lean.

 

[Fastest Caskets]

lean could be a vaccum leak, did you say that you had the intake off? I hope you don't think I'm poking at your mechanical skills, but when i first started to dabble in cars, I've missed vaccume lines and even disturbed/broken intake gaskets while doing exploratory surgery...

 

[Relvie]

It was the fuel pump thanks all who tried to help.

 

[MrShorty]

Since diagnosis is often most of the battle, could you explain how you determined that the fuel pump was at fault?

 

[Relvie]

Well I had a ford tempo a couple years ago that would do the same thing when it was hot outside. Only it would shut off for about a half hour. I just recently have changed the fuel pump but it was an airtex so I figured it would probably be the problem since it had similar symptoms. So i switched it to a boush and now its all good.

 

[Fastest Caskets]

sweet

 

[Relvie]

Ugh thought I had it fixed... the sputtering and stalling during the daytime seem to be fixed. But now my idle is bouncing around a lot and still running rich. Also still getting code 41... getting very frustrating almost ready to park it at the bottom of a lake...