Car surging/bucking on rough roads. Suggestions?
 

I noticed yesterday that as I was heading over a rough road, my car (1995 LT1) would surge/buck (for lack of a better way to put it) and the engine light came on. The once on smoother road, the light went off and the car was fine. The car had done this last year as well but it went away. In addition, I've noticed a clicking sound under the hood and the car seems to be running rich. Maybe I've got a bad plug wire (did have one burned off 2 years ago but it's long been replaced and everything seems to be ok) and the rough road is causing the wire to move enough to cause the problem?. Just wondering if anyone had suggestions considering the way the car acts up on rough roads. Like I said, if I'm cruising along a smooth stretch of road, everything is fine. Anyone have this happen to them?

Thx folks

Why not pull the code(s) and find out what turned on the SES light? Sounds like a loose or corroded harness connector, etc. Very good chance the code will point you in the right direction.

Tried to check the code last year with my buddies scanner but it didn't detect anything. I'm assuming that the code should still be stored in the PCM even after the engine light has gone off correct?

Yes. The codes stays stored until the car has been driven a pre-determined number of "drive cycles" without the problem coming back. Do not disconnect the battery, or they will be cleared.

What scanner did you use? A lot of people see the 16-pin OBD-II ALDL connector on the 95's and assume they can use an OBD-II scanner. Won't work, because the PCM is OBD-I. You need an OBD-I scanner with a 12-pin->16-pin adapter, or connect the 12-pin scanner plug using jumper wires, as shown on Shoebox's site:

http://shbox.com/1/xraycable.jpg

Problem solved (I think) - I checked all the vacuum hoses, electrical connectors, etc... but nothing. So I started to strip things off. When I took off the intake elbow, I found a small crack at the bottom of the elbow (never to be seen from above). Sure enough, with the car running, if I squeezed the elbow slightly to open the crack, the car would shut off. I have the hole patched now just to see if the behaviour is now gone and before ordering a new elbow.

Just wanted to pass on this info for anyone else who might be having similar behaviour and like me, wouldn't think of checking the elbow itself.

Cheers