I have an 89 wrangler with a 6 cyl. Runs good but on highway when I shift to 5 th gear it starts to loose speed ?
The clutch is slipping, most likely.
Very well could be a compression issue with the engine. I had the same problem with my 87 wrangler. Mainly had issues on the highway, especially going up hills.
Search Jeep Wrangler Questions
Jeep Wrangler Experts
Related Models For Sale
Used Cars For Sale