Rough Idle when cold - dealership no help so far. 2002 Chevy Suburban
We got a 2002 Suburban 1500 from our local Chevrolet dealership on December 18. It ran fine upon test drive, etc. The Service Engine Soon light came on on the 22nd, but noticed nothing else irregular. When I started it up in the morning of the 23rd, I noticed a rough idle. Every few seconds the vehicle would shudder, and the RPMs would dip. This continues until the car has driven a few miles and warms up.
On the 23rd, I took it to the dealership to see if they could take a peek since we'd only had it a few days. They did, said the computer threw a code (didn't tell me which one) and they replaced the Mass Air Flow Sensor and brought it back to me. The SES light was off and of course no rough idle because the car was warm so I thought it was fixed.
Today, the 24th, get in it and again, rough idle is back. Same symptoms as before, except the SES light is off. So I thought for a minute, turned off the car, turned it back on and no SES light comes on at all to confirm it's even working. Those guys must have disconnected the darn thing, is all I can think.
So now, I'm mad, I have a dealership who apparently has no interest in fixing it right.
More info - it blows white smoke out of the exhaust.
The rough idle only happens when the vehicle is cold and in park. Doesn't do it if it's in gear.
Yesterday evening, the Service Engine Soon light was coming on (not staying on, just flashes when starting the car, but this morning the SES light again doesn't come on when you turn the key to on. Something wrong with the computer maybe?