I have a 1999 monte carlo z34 with 65,000 miles. Over the past year, my car has would surge every now and then, usually worse in the winter months. Lately the surges have been so bad and last so long, i feel as if im going to break down or damage something on the car. The RPM's jump all over the place and im constantly jerking back and forth inside of the car. The car will surge on a hill as well as a flat road, it doesn't matter anymore. I had it in the shop, but it didnt act up for the mechanic. There are no lights on in the dash and there are no codes to read cause I had it scanned. If anyone knows what the problem is, I would appreciate your help!

 

first thing that comes to mind is a bad fuel pump or fuel pressure regulator. if that's what it is, get it fixed NOW. don't want it to leave you stranded on the highway in the middle of nowhere. i would suggest taking it to a different mechanic if the other one couldn't figure out what it was.

 

I am having the same problem but it seems to be far more intermittent than yours in my 99' 3.8l. I hd the Fuel pump replaced about a year ago, replaced the upper intake manifold about 1 1/2 months ago. Replaced the fuel filter, air filter, spark plugs and wires today and it still did it some on the drive home. I attempted to clean the MAF sensor (did not damage it) but I'm not sure I did the most thorough job on it as I was was a little terrified about damaging it. That unit was replaced 3 - 4 years ago. Not sure what else to do, Fuel Pressure regulator? Everyone seems to default to a bad Cat on this forum so I guess I should go get that tested. Does anyone have a good idea one where to have that done? I live in Springfield, Mo at the moment btw.