Hey, I have an '86 trooper that wants to buck- like it is starved for fuel. The carburetor is relatively new, with less than 15,000 miles on it. I noticed that it first started happening at highway speeds only. It would usually stumble and buck for a moment, until I push in the clutch and give it gas and then it would be smooth sailing again... for a while. It has increased in duration and frequency. Last night it was worse as ever, but I limped it the 60 miles or so to my destination.
It doesn't knock or miss like it is a timing problem. I have noticed that the fuel filter gets pretty dirty quick, but I just replaced it with a clear one and it looks really clean in there. One thing I do notice is that when the problem is evident, my idle speed will drop also and sometimes will cut out all together, killing the engine. I am thinking perhaps fuel pump, but am wondering it may be something more simple. So please, if anyone else has experienced these problems, respond asap as I need to go the 60 miles back home tomorrow evening.
Thanks in advance
-Steve

I just went and ran her around the block and she did fine! I am beginning to think that this may be the dreaded VAPOR LOCK....
any suggestions?