1993 C4 studdering
Thread Starter
2nd Gear
Joined: Nov 2021
Posts: 2
Likes: 0
1993 C4 studdering
I could use everyone's help. I have a 1993 C4 that is shuddering at light throttle. It is when the 1 to 4 light is on. If I give it a little more throttle it doesn't do it. It also doesn't seem to be as fast as usual and exhaust doesn't sound the same. Only code that I have is a C34.
Drifting
Joined: Feb 2016
Posts: 1,384
Likes: 339
From: Simi Valley CA
I have the same thing with mine, but hardly noticeable. My first step was to open the hood at night with it in a dark spot while idling. Mine looked like a xmas tree under the hood with blue sparks flikering all over the spark plug wires. These wires go through several brackets, engine pullies, next to hot exhaust manifolds, smog pipes, etc so they are prone to wearing out and arcing. Replacing the wires is a job. I would suggest making your own wires as I bought a 8MM kit and it doesn't fit good. All the factory kits are 7MM and I think that is barely adequate for this car.
Racer
Joined: Jul 2012
Posts: 383
Likes: 86
From: Northeast Ohio
"Shuddering" and "exhaust doesn't sound the same"...makes me wonder about the cats....could they be getting clogged?
My LT1 experience is from a 95 ImpalaSS. The exhaust manifold bolts to the rear of the engine were prone to breaking (especially on the passenger side on the Imps). This would cause a small exhaust leak that would slowly increase over the years. The leak allows air to be siphoned into the exhaust stream, the O2 sensor detects the extra oxygen, the computer thinks that it should add more fuel to take advantage of the oxygen. Except there is not extra oxygen in the combustion chambers, the extra fuel is not burned, the fuel hits the cat, and deposits begin the accumulate.
My LT1 experience is from a 95 ImpalaSS. The exhaust manifold bolts to the rear of the engine were prone to breaking (especially on the passenger side on the Imps). This would cause a small exhaust leak that would slowly increase over the years. The leak allows air to be siphoned into the exhaust stream, the O2 sensor detects the extra oxygen, the computer thinks that it should add more fuel to take advantage of the oxygen. Except there is not extra oxygen in the combustion chambers, the extra fuel is not burned, the fuel hits the cat, and deposits begin the accumulate.
