Hello, This is my first Isuzu. It is a 1993 Trooper LS, 4X4, automatic. 232,000 miles. It idles fine and revs fine. However when in gear it has a bad miss or seems to be missing, when on the gas it is very rough and takes forever to gain speed. It seems to be backfiring ( popping in the exhaust). The previous owner gave up on it after investing lots of money. It has new coil packs plugs and wires, I can see those and I pulled 2 plugs 1 from each side and they are gaped at .040. He says it has a new fuel pump,fuel lines,filter. The truck was on empty when I bought it about 3 hrs ago. I put 20 bucks in it so I know the gas is good. He also had the timing belt replaced,it looks new because the top cover is missing. I'm thinking it's a timing issue, but not sure.Any ideas would be helpful. Thanks.

 

thats what i would do, get the timing set and see if that works. sounds like it might be off a tooth or two. get it set and report back.

 

ok, I found my troubles. I had a friend of a friend check the timing and it was correct. So long story short I pulled all the plugs and found 4 of the 6 were bad. My luck the first 2 i pulled were the good one's. I started from scratch and found 1 bad coil pack and found 2 injectors not firing. I pulled the intake and cleaned the injectors and I am happy to say it runs like a brand new truck.