OK, new to the forum, so I hope you can help. I have an '01 Grand Cherokee Laredo with the I-6, & 4WD. Absolutely wonderful vehicle, as she has 218,000 on it and still running good.
Anyway, there are two things are going on right now that concern me. First, at highway speeds I can accelerate and the tranny drops down and immediately back up, almost like the old 4 barrel carbs used to do when you floored them. I also have the problem happen when I am cruising down the highway with the cruise control on. I basically constantly drops back to 3rd and immediately goes back to 4th/OD. To the point that cruise control is useless. This happened a long time ago and the dealership installed some kind of new module that ended up costing me about $250 with parts & labor. Obviously I need to do this myself if at all possible.
Second issue happened last night while in a drive through line. As we crept along, it really started vibrating, almost like it was something in the fuel line. But, when I put it in neutral, it stopped. Put in drive, it vibrates and hesitates like crazy. With cars in front of me and cars behind me, I had to do this the whole time for fear of it shutting off. About 5 minutes after it started, it was gone and she purred like a kitten again. So far I haven't been able to get it to do it again, but with Christmas shopping and this being the wife's DD, I want to find a fix ASAP.
Could these both be the result of a bad module or sensor somewhere or am I looking at two separate issues that someone beyond a shadetree mechanic (me) needs to look at?
Thanks in advance!