stumbling/bucking problem
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Joined: Feb 2007
Posts: 95
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From: belmont maine
stumbling/bucking problem
Hi, I have what I could describe as a stumbling/bucking problem. The problem began last fall, I stored the car over the winter, and the problem did not magically solve itself this spring. Here is the summary: car starts fine and idles right on point. Drives great, no problems, until maybe 10-15 minutes in and the car warms up (into the 170 degree range). Then upon acceleration--in the low to mid 50 mph range-- (especially going up a hill) the car bucks/stumbles and feels like it may stall out. There is a clunking sound coming from what appears to be passenger side rear area. I feather the gas some and voila the problem goes away. Car runs between 192-197 degrees. For the rest of the day, either long driving or frequent stops and starts, the problem does not appear. The next day, like clockwork, it appears again and like clockwork goes away. All filters etc. changed last year. Would a clogged cat cause this? How do you check? Any other suggestions? Sorry for the long non-scientific description. This bugs me and might be a sign of something more drastic. Car is a '92 auto with 93K miles.
Thanks, Larry
Thanks, Larry
Instructor
Joined: Aug 2006
Posts: 140
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From: St. Louis MO
I think we have the same problem. My 94 LT1 stumbles badly right as the thermostat is opening up. Runs great when cold or hot, just the brief problem... only lasts a minute or so until warmup is complete. I figure it must have something to do with going into closed loop mode (which means I disagree - with all due respect - that it's an opti problem). I just bought the AKM cable and TTS Datamaster software to start logging engine diagnostics, so I hope to get this solved in the next couple of weeks (I'm out of town a lot, don't have much time to spend on it right now). I'll let you know what I find.
Burning Brakes
Joined: Aug 2006
Posts: 1,123
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From: Rockland County NY
I had a similar problem on my 91 L98. I called a local repair shop who does quite a bit of Corvette work. He said that with the car idling, pop the hood and give the computer a rap. If the engine stumbles, that could be the problem. It turns out that was the problem. A reman unit was a pretty cheap fix.
Pro
Joined: Mar 2006
Posts: 521
Likes: 23
From: Golden CO
stumbling, water pump/optispark
I had that but it got serious, car would not run and it looked like Optispark, turned out it had just got wet in there, maybe water pump problem, I think the pump was replaced and the car has been solid for years since, '92 with 135k now. Good luck, doubt yours is this but fyi.
