Ok...get ready this is going to be a lengthy post so
I can try and cover all questions up front.

1995 Trooper 3.2 SOHC Auto 165,000 miles
4-5 inch, 34 inch tires, 4.77 gears
engine stock except K&N box filter which as
been there 40,000 miles (yes been cleaned)

Currently the truck is having a real tough time running under 2,000 rpm at idle it is the worst. Once this truck gets approaches 2,000 rpm the frequency decreases to a point either it stops happening or I don't notice->(not likely). This is the second time it has been like this in the last 3 months. It is constantly missing and stumbling, like 2 or 3 times a second. It appears to only miss every few seconds when I first start it, and continues to get worse as the truck reaches full operating temp. It has been going on at this rate for about 5,000 miles.

For those that have the oil in plug well situation it acts very much like that (mine had that issue-previously Fixed) So when this started first thing I did was check all plugs and wires. Didn't see a problem, however still replaced plugs and wires just in case I had a bad one that wasn't obvious. This didn't help. So I replaced fuel filter...nope.

Then I replaced all coil packs and it solved the problem for about 5,000 miles. Now it has returned again. Is it really possible that the new coil pack have gone bad in less than 2 month & 5,000 miles? Sounds to me like there is a larger underlying issue, that the new coils packs were able to hide for a short period of time.

Ok guys ask more questions and lets get to the bottom of this.

Thanks In Advance
MARK

WHOSE PLUGS AND WIRES DID YOU USE , IF THEY ARE NOT THE FACTORY WIRES AND THE PLUGS RECCOMMENED, NGK, THIS MAY STILL BE THE PROB, ALLSO IF THE WIRES ARE CAUSING THE PROB, YOU COULD DAMAGE THE NEW COILS , IF THE WIRES ARE OPENING UP INTERMITTENTLY, THE AVAILABLE VOLTAGE FROM THE COILS CAN GO PRETTY HIGH IN AN OPEN CIRCUIT SITUATION AND THEY CAN THEN START ARCING ACROSS THE TOWERS OR INTERNAL ARCING, AND THIS IN TURN CAN DAMAGE THE IGN CONTROL BOARD THEY SIT ON, . MAKE CERTAIN THE PLUGS ARE GAPPED CORRECTLY .041 THOUS, AND THAT THERE IS NO OIL IN THE PLUG WELL AND INSPECT THE BOTTOM OF THE PLUG WIRES VERY CAREFULLY ..JERRY

Thanks Jerry, but all those solutions have been exhausted. I have always used factory parts since I bought the truck 7 years ago. I replaced the plug well seals about 1 year ago and no leaks as of last weekend. The NGK plugs are about 3 months old and are looking great and gapped correctly, factory wires 3 months old. Coil packs 2 months old.

What are plug well seals? Have I missed something?

The spark plugs go through the top of the valve cover into the head. Attached to the head are tubes creating a well for the plugs, the seals are between the valve cover and the tube. Which often leak causing the tube to fill with oil and short out the plug & plug wire.

SOUNDS LIKE YOU HAVE THE IGN SYSTEM COVERED , WITH ONE EXCEPTION THE IGN MODULE ITSELF WHICH DOESN,T GIVE TOO MUCH TROUBLE IT USUALLY WORKS OR DOESN,T , HAVE YOU BY CHANCE CHECKED THE FUEL PRESSURE AT THAT MILAGE THE FUEL PUMP MAY BE LAYING DOWN ON YOU, TRY PULLING THE VAC LINE OFF OF THE FUEL REGULATOR AND SEE IF IT TRIES TO RUN ANY BETTER , THIS WILL INCREASE THE FUEL PRESSURE AND MAY GIVE AN INDICATION OF THE PUMP BEING BEAD , YOU NEED TO HAVE AT LEAST 28 PSI TO RUN ANYWHERE NEAR CORRECTLY , FIND OUT WHAT THE FUEL PRESSURE IS IF YOU HAVE A PRESSURE GAUGE JERRY

Mark: I was chasing down something similar w/ my trooper. I felt a heavy drag on my engine at very similar RPMS and engine temps. I felt that issue was fuel or air realted.

I cleaned air filter, sea foamed the intake, techron'd the fuel system, replaced the fuel filter and lines (they started leaking). The trooper is driving much better.

I've picked up a new cat, o2 sensor, and glasspack muffler, but I have not had time to install.

Thanks Jerry I do have the tools to check the pressure so that is what I'll be doing the next chance I get. Is the fuel pump in the tank?? Because I probably replace it anyways.

YES THE FUEL PUMP IS IN THE TANK, TAKE A LOOK AT THE FUEL RAIL ON THE ENG, SOME OF THOSE ENGS HAD A FUEL PRESSURE PLUG RIGHT ON THE RAIL, IT LOOKS LIKE AN AC PORT , IT SHOULD HAVE A BLACK PLASTIC CAP ON IT AND YOU CAN SCREW A FUEL PRESS GAUGE RIGHT ON IT , IT HAS SCHRADER VLV IN SIDE SO IT DOESN,T SPIT GAS VERYWHERE JERRY

Well, I was unable to get my fuel pressure gauge attached (lack of space), but I did remove the vacuum line from the fuel regulator and it made the truck run alot worse!!
So unless I come up with something else soon it appears and I'm dreading the idea but maybe a trip to a dealer is in the future. Anyone know of a good isuzu service department in central virginia...lofty expectations...so does anyone know of any isuzu dealers in central virginia.

Mark