My '90 coupe bucks when trying to maintain 40ish on an uphill grade. It is as smooth as silk on the level. I can prevent this from happening by driving through the troublesome area. i.e. keeping the rpm's higher. The bucking seems to be at about 1500 rpm's. Again, if I accelerate through this area there is now problem. I originally thought by down shifting out of overdrive helped - but it is either getting worse or I was keeping the rpm's up on those occasions. I believe the latter is the case. Is this a problem I should be concerned with - a symptom of a greater problem - or is it just a nuisance of no real concern? [img]images/icons/confused.gif" border="0[/img]

[padgett]

Is probably secondary ignition (coilpack, wires, plugs) and if you know the last two are good, then one of the coils is probably marginal. Low RPM/high load/top gear is where it will show up first.<P>Are other possibilities but check the ignition first. <P>ps - will not set any codes.

[BP]

I had a similar problem with my 1989 Reatta. It was so rough I was convinced it was some sort of mechanical problem. Transmission slipping or something like that. I discussed it with my Buick Service Manager, he suggested / suspected a weak ignition coil and maybe new wires and spark plugs. I was shocked at his response, but he was so confident with his diagnosis I took his advice.<P>After replacing the coil, wires and plugs. The bucking is GONE. The car performs smoothly at all Rpm&#8217;s and under any load conditions. It took me about an hour and a half to replace coil, plugs, and wires. I spent $54 for new Wires and Plugs. It was time consuming feeding wires neatly around / through alternator and those funny looking heat shields were a surprise too. Regarding the ignition coil, be sure to keep track of the wire connections under the coil. Care needs to be taken to keep track of which wire goes where as you tip the coil upside down so things get reversed. I think the new coil was about $100.<P>Good luck<BR>VR<BR>bp