Update -

First of all...thanks again for the feedback.

I ended up having it towed to a garage nearby that specializes in Japanese vehicles.

I had to replace the starter as the motor wasn't turning over. Once this was in place, I was back to the original problem.

Unfortunately, they're telling me that it's most likely a bad transmission, and from what I've seen so far, this expense almost equals the blue book value of the vehicle itself.

I was a little concerned about his diagnosis as he probably doesn't see A LOT of Troopers, so I also decided to drop by a local Isuzu dealer to talk to a mechanic that knows them well.

I explained to the Isuzu mechanic how the vehicle seems to slip out of gear and rev high before catching again once I've slowed down. I also mentioned that it only really happens once it's warmed up a bit. Based on this info...he also thought it was a bad transmission.

I asked about the intake manifold gasket perhaps causing the problem - but he mentioned that the Troopers transmission is all electric, so he doubted this. (I've actually read about problems that seem to be related to the transmission actually being the IMG)

I also asked about the EGR needing cleaning (based on what I've read here and other forums) and he indicated that the Trooper would probably be stalling a lot if this was a problem.

So...I'm kind of stuck. I really hate to invest $4000 in a new transmission for a vehicle that's notorious for other engine-related problems.

But I'm also thinking in the back of my mind - what if they're wrong? What if IT IS as simple as an intake gasket needing replacement?

Not sure what to do here. Could I find a rebuilt transmission for less that 4k?

Thanks again for all the input. Here's the answer to the questions above.

120,000 miles on Trooper. Service was sporadic..and I'm paying for this now (live and learn). Not sure on the oil burn rate exactly. This is the wife's vehicle and I check it every two weeks. Probably a quart every 700 miles or so.

Dave