I have a 98 ram 4x4, auto, 5.9 with 150k. It has seemed to have slowly lost some power over the past year and now after driving on the highway for a while when I get to about 3000rpm it starts to stumble. But when I let off the gas and let it shift to the next gear it is fine till it reaches 3000rpm again and it starts to stumble again. I put a low temp thermostat in last summer because of overheating problems but I don't think this is the problem. I am guessing fuel pump, fuel filter or injector problems or maybe even cat converter. Any ideas would be much appreciated. Thanks Also I've done a vacume and fuel pressure test and everything seems fine.I've also done an air induction service.
The problem has been fixed. It was a clogged cat converter.
Sunday, January 7th, 2007 AT 3:23 AM