This has been going on for 5 years now. 1994, 4.9 l, stickshift. Have just replaced coil, new spark plug wires, new rotor, new EGR valve, new fuel pressure regulator. And the problem persists! Here is the problem:

When this first began, it happened only if I drove the truck maybe 5-20 minutes, then stopped for 5-20 minutes, got back in. It wouldn't start. It turns over, but it would be like it couldn't get enough fuel. If I floored, it might not die--or it might. Worse in warm, humid weather. But now, it can happen even when it is freezing here in Michigan. Until the last year or so, I would usually have to let it sit for 5 minutes to get it to start. Now, I can get it to start after 2 or 3 tries, without waiting. Other times, it runs great for days.

The other problem is, when driving it will hesitate or stutter--like, uhh, uhh, uhh. Like it is not getting enough gas. It does this entirely intermittently in a single trip--it might do it on one occasion during a 20=minute trip, or it might do it 5 or 6 times, or it might not do it at all. It only lasts for maybe 30 seconds or so. Can drive for days with no problem. Worst at 19-23 mph. This problem has diminished almost to the point of being unnoticeable since the above parts were replaced.

I also cleaned the EGR valve sensor, which was full of oil. But I only cleaned the sensor part--I think there must be some other part to it. Mechanics have done the other work on it. Oh, and I cleaned the IAC.

A fuel pressure test was done, no problems found.

Replaced the fuel filter 3 or 4 times about 10k ago. Like everything else that has been done, it seemed to help for a few days or a week, then back to the same thing.

Emergency brake was sticking. Cables now cut off. Probably warped left rear disc. Maybe that has something to do with the hesitation?

Ideas?

 

THose years the On Board Diagnostics were being switched over to OBD 2, you have OBD1. My experience with mustangs in 94-95 years, they are fickle, they don't show the codes correctly, they come on and go off(my 96' F150 does it), which is a flaw in the design.

Saying that, I would check the ----Crank Position Sensor.---- They're usually cheap, maybe swap it out, all "Emission" sensors need replaced eventually, it has "limits" it operates within, until its "stays" outside those limits it won't turn the CEL on for good.

Also the check the -----Ign COntrol Module------ that sits on the distributor will do that when it gets hot, my Mustangs did that as well, then in 94-95 they moved it to the fender well to stay cool and those problems went away.

All these sensors hang out on a hot a** engine for 20 years, they work and they don't work, the inards are probably just warped.

Your IAC, EGR etc will do those exact symptoms, you might wanna replace them, not just clean and oil them. Use Motorcraft sensors only btw.

-----Check Timing------- It can move around over time, I always put a mark to watch it.

 

Thanks!

 

I can't figure out how to configure my settings so that I get instant replies to this thread. Thanks.

 

I would guess distributer. The bearings can get worn causing intermittent problems. Also when the pickup sensor is going out, it can cause intermittent problems. Try buying a rebuilt unit from a parts store that will let you return it if it turns out to not be the problem. From your description I'd say it's a high probability this is your issue.

 

Got new distributor cap, but not distributor. So you think a new distributor, then?

 

Yes the distributer,

 

Same thing happening to mine and someone else mentioned distributor. I changed cap/roter/plugs/wires.

I was hesitant at first and then I bit the bullet and spent about 75 bucks. Did it for me, and my symptoms were about same as yours to the T.

 

My mechanic says no way the distributor. We changed the downstream oxygen sensor. Everything we do helps a tiny bit. Thinking about the MAP sensor. He says ICM is fine.

However, I still get the hesitation a tiny bit.

My gas mileage is lousy. I used to get 14 mpg with this truck, even in the city. It went down to 9.5. I drove it only highway miles the other day (about 80 miles), filled it up, and it was getting 12 mpg. Not good enough. Don't know city miles yet. The power is not really any better, either.

 

Bump. Ever get better outcome? Changes?