XJNKY

Alright guys, I did post this over at JF, but I've often found much better technical details here. So here's the copy-and-paste version. Let's have a race and see which forum can solve it faster

98XJ, 4.0, AW4, 167K

I have the standard 97+ cluster problem. I've had it intermittently for a while. I'll be driving, all the gauges just go dead. I thump the dash, they come back, no biggie.

So, yesterday on the way to work, my speedometer starts jumping, and going crazy. It started just jumping +5mph, -5mph, and quickly escalated to 0-100 fluctuations. I know there's a lot of gauge problems in this year range, and I knew I was eventually going to have to remove the cluster and clean the connections. But the Speedometer is the only thing malfunctioning at this point. Not a huge deal, but an inconvenience.

Then on the way home yesterday, had to come to a complete stop for someone making a turn, and when I took back off (flat ground), the engine started cutting out. Speedometer is basically staying at zero at this point, but it does jump every now and then. It cuts out probably 10-12 times in an 8 second window. I floor it, it still cuts out a few times, but then it suddenly clears up.

A few miles up the road, have to climb a steep hill, 2 lanes, behind a very slow moving farm truck. Try to pass them, same thing. It cuts out 6-7 times in about 5 seconds, and then clears up. So it seems to only be while trying to accelerate.

The tank of gas before last I had suspected of not being top quality, because it started running noticeably worse after a few miles away from the gas station, but I've filled up elsewhere since then and it had gotten peppier. But I'm on 1/3 tank, so when I get home, I dump in a bottle of HEET, just in case it's a water issue.

This morning, same thing. I stop and get some gas, just to get some fresh gas in there... still, no change. I also checked my battery terminals (nothing else electrical seemed to be acting up), and the negative terminal wasn't tight. In fact, it wouldn't tighten down until I deformed the connector a little. But it is tight now, and still cutting out.

I've noticed it does it if I make the transmission kick down, or it does it when it downshifts naturally (not every time). It also did it at a stop light this morning (one hiccup) as I took off.

I should also note, the day before yesterday, I drove through a bunch of scrub brush and small trees, and when I get home tonight, I'm going to crawl under and made sure the wires to the speed sensor are intact.

So... Is this connected to the speedometer issue, or is it just serendipitous? Anyone ever had these problems manifest at the same time?

My thoughts:
A) completely unrelated issues that just happened to show up back-to-back
B) speed sensor failure, nothing to do with cluster connection, causing computer to think it is speeding over the governor limit, and cutting the engine out? (is this possible?)
C) bad ground connection somewhere
D) Gremlins

Cptn Dan

I'm having a similar prob with my 96 sport.
Anyone have an answer to this yet?

XJNKY

Yes. It took them 5 days at the dealership to find it. I had a damaged wire somewhere in the vehicle speed sensor circuit that was shorting out (to either the body or the transmission) and was causing all kinds of erratic reads. They said the computer showed it going 100+ while sitting idling in the bay. That was causing the governor to cut the engine out, and causing all the weird transmission shifting issues. (won't shift down into 1st if it thinks it's going 65mph). They repaired the wire, everything works again.