Hello,
I have a 1994 Trooper with the 3.2 DOHV engine. About six weeks ago, I was driving when all of a sudden my vehicle died. I pulled over to the side of the road and tried to start it back up. It seemed to be having a fuel issue and was attempting to start as I feathered the gas pedal but continued to keep stalling. About the 5th attempt, it suddenly started up and ran as if the problem had never even happened. About 2 days later the same thing happened. I figured I would change my fuel filter and start there. This didn't cure the problem, as it happened again about 4 days later. Next, I tested my fuel pressure regulator and it tested fine. So my thoughts led me to begin to suspect the fuel pump. I changed the fuel pump and all seemed to have been cured when suddenly after almost 90 miles driven on the new fuel pump, said problem happened again. This time, I had went to the grocery store and when I came out and started the vehicle, it was evident that it was running extremely rough. The gauges on the dash (RPM) were slightly bouncing as the engine began to stall out and the check engine light was flashing some but I could feather the pedal to keep it running (very rough, but running). And like all the other times it seemed to just go away and begin to run correctly again. I have now ordered a new ECM MAIN RELAY as my next venue of guess work. If there is anyone who has dealt with this issue and has any advice as to where to go next if this relay doesn't fix the problem it would be greatly appreciated. I have had the Trooper for just over 3 years now and I really do enjoy driving it. But it has become very frustrating to have no confidence in my ride. It has 162K miles on it. I didn't mention that before.

 

well, I replaced the ECM relay this morning and I will have to just wait to see if the problem occurrs yet again. But any advice would be welcomed. Thanks.

 

Where the heck is the Fuel Pressure Regulator? I'm having some issues with mine but kind find the thing. A few things about yours, Kind of sounds like a bad coil pack or even a faulty TPS. You can test your TPS with an ohm meter pretty easily.

 

Thanks for the advice. Well, the ECM Relay didn't solve anything as the problem happened yet again. Now I am going to test the TPS and also the MAP sensor to see if they are faulty. If those are fine I will move on to the Camshaft positioning sensor. There can't be too many more things that it could be. Hopefully this is almost done as this has been a bit frustrating. Thanks again for the advice.

 

Hi Logman i have a 2002 trooper with the 3.0 dohc engine in october it started loosing power and then cutting out. It would then restart after 20 mins. After having it serviced there was still no difference so ended up sending in to an Isuzu dealer who could still not find the fault. It was then sent to isuzu uk who finally diagnosed a Rail Pressure Control Valve.
Hope this helps and dosent take 6 months to fix like mine has.

 

I would be suspect of your new fuel pump. Possibly, your gas tank has developed rust or debris in the tank. Although I've not experienced that with my trooper, I've had a number of older vehicles what chewed through fuel pumps until I removed the tank and had it cleaned and sealed. Your mileage seems low so I wonder that your trooper has spent some down time, not being driven, and possibly with low or no fuel in the tank for some time. This is when the inside of the tank can begin to be affected and corrosion can develop. Your new pump is working better than the old one, right? But still hiccupping, maybe chewing up some rust and spitting it through. If the problem begins to get worse or you just lose fuel pressure altogether, you might look into the gas tank. Good luck.

 

The tank was spotless when I changed the fuel pump, but I do appreciate your advice. I think I have it narrowed down now to the Camshaft Postion Sensor or the Throttle Position Sensor. I have yet to get the problem to occurr in front of a mechanic is probably the most frustrating factor in this process. A mechanic told me the Throttle Position Sensor is unlikely because it wouldn't do that while driving so I am going to replace the Camshaft sensor and see what happens. The weather got nicer so I have been riding my motorcycle most days now. But hopefully this will be the final thing to fix it right.

 

I wouldbe interested in your thoughts on why you believe the cam shaft sensor is at fault. if you could just discribe the cause and effect of your process I believe you could find the aswer more directly .......The next time your vehicle dies.......turn the ignition switch on and look at the panel lights ....Is there anything flashing?......
Are you under the idea that your ignition timing is faulty? a simple test place your vehicle on flat ground without the parking brakeset but in park does it roll a bit before it makes contact with the parked transmission? does the engine tachometer vasilate at Idle? there are some obvious indicators of wear issues that you are not including in your post.
one of the most obvious is a vacuum leak in your intake manifold. does the engine smoke? what color is the tailpipe is there a heavy film of black soot inside the tailpipe?

 

2 Troopers now in my world have a similar issue. I have never personally experienced it. On the highway, partial tank of gas. Stalls like running out of fuel. Give it a rest and then it's fine again.
In my experience resistors, fuses and relays are usually the culprit. They get hot, metal expands and contact is lost. Both Troopers had their fuel pumps and filters replaced. Yes, I agree that a sensor could do it too. Start with the simple cheap stuff and work your way up. If no Fuel Pump noise after it stalls (key on), check volts at the FP relay to see if that circuit even has power then jump it to verify FP operation. Swap relays with other circuits with same type relay, replace FP, Main, PCM etc fuses even if they look OK.
Let me know what it was when you figure it out!
Harry

 

Anyone ever get a fix on this issue? I have the BEST mechanic on it, but even he is scratching his head!?! Frustrating...

On the highway, various gas tank levels. Sputters like running out of fuel. I CAN "feather" the gas pedal and keep it going. Gas mileage goes from normal 15mpg to around 10mpg. Give it a rest and then it's fine again.

Replaced fuel pump, fuel filters, points, plugs, ECM...