I have a manual transmission '97 Jeep Wrangler Sport. Recently I was driving on the interstate at about 78 mph and went over a bridge. The bridge was rather rough and when I hit the bump my Jeep lurched forward and made a sound as if I had just pushed the clutch in. Shortly after, while on flat ground and driving about 70, it did it again. This time when I felt it begin to lurch and heard the noise I looked at the guages and noticed that my tachometer dropped and then returned to normal. I was driving in the Jeep for about eight hours that day and this occured about four times. I can only equate the sensation of the lurch of my Jeep to a burp (very sudden and slightly violent... ha) and the sound it made was identical to the one it makes when I push my clutch in at higher speeds to downshift. Has this happened to anyone else? Does anyone have any idea what could be wrong with it? Any help with diagnostics would be greatly appreciated!
12-02-2011 05:53 PM
U joints come to mind.
12-03-2011 04:58 PM
Can you describe this sound in some detail? What you describe sounds like an engine stumble (especially with the tach dropping and coming back up). Could be dirty injectors or funky gas, especially if it was cold.
12-03-2011 05:18 PM
I have a fleet of vehicles, and one of them had the same symptoms. It would "hickup" or "lurch" every now and then, but I could not force it to happen (and I tried). After a couple years of this, one day it just died. Towed it to the shop for diagnosis, and it was a bad coil wire from the coil to the distributor. The wire had been grounding out against the air intake system, and the lurch was when the spark hit ground, but, because the symptom was infrequent. As the wire continued to deteriorate, eventually it died. The wire wasn't particularly old, but was abraided by rubbing.
Not saying that's your problem. Just one more idea.
12-04-2011 12:53 PM
Ouch! You could go stark raving mad chasing something like that down... But it is a really good idea, I hadn't thought of a loose or abraded wire, and considering the rats nest of wiring under a tj hood it would be a good idea to follow the wiring from the distributor to the coil.