tigeraid
06-03-03, 18:08
Hey guys, just bought a beauty of a '94 9C1. I love it and all, but it's having a progressively worse intermittant stumbling idle.
It's very random,. and the CEL doesn't come on when it happens (tho that has flickered one once or twice not related to the stumble, only to go away shortly after).... Cruising just fine, then coming to a stop as I slow down, the engine starts to buck and stumble. By the time I come to a complete stop, the computer takes 2-3 seconds and then normally the idle smooths right out. However every now and then when it happens, the stumble gets SO bad that the computer doesn't recover, and it ends up stumbling and coughing as I begin to accelerate. Once I get up into the revs, there's no issue and she'll pull like crazy.
I'm bringing it to the dealer on Thursday to pull the codes, hopefully that reveals something. Unfortunately the '94 with the 4.3 L99, for some retarded reason, can't use a conventional CEL code reader, even though the '95 4.3 and 94-95 LT1 both can (??) ... so I bought one of those, and all it did was flash the CEL constantly, no codes. So I returned that.
Out of curiousity I tried pulling the vacuum line off the EGR and plugging it, to see if the EGR was the problem. Didn't seem to make a difference. And I haven't seen/heard any obvious vacuum leaks but I'm almost hoping that's what it is. Any ideas based on the symptoms guys?
P.S. - I haven't found a DIRECT connection with this, but I've noticed it happen often after reasonably brisk acceleration. If I putt around it rarely seems to happen, but when I accelerate even, say, 1/2 throttle, then coming to a stop at THAT point is when it seems most common. But I'm not sure on this.
It's very random,. and the CEL doesn't come on when it happens (tho that has flickered one once or twice not related to the stumble, only to go away shortly after).... Cruising just fine, then coming to a stop as I slow down, the engine starts to buck and stumble. By the time I come to a complete stop, the computer takes 2-3 seconds and then normally the idle smooths right out. However every now and then when it happens, the stumble gets SO bad that the computer doesn't recover, and it ends up stumbling and coughing as I begin to accelerate. Once I get up into the revs, there's no issue and she'll pull like crazy.
I'm bringing it to the dealer on Thursday to pull the codes, hopefully that reveals something. Unfortunately the '94 with the 4.3 L99, for some retarded reason, can't use a conventional CEL code reader, even though the '95 4.3 and 94-95 LT1 both can (??) ... so I bought one of those, and all it did was flash the CEL constantly, no codes. So I returned that.
Out of curiousity I tried pulling the vacuum line off the EGR and plugging it, to see if the EGR was the problem. Didn't seem to make a difference. And I haven't seen/heard any obvious vacuum leaks but I'm almost hoping that's what it is. Any ideas based on the symptoms guys?
P.S. - I haven't found a DIRECT connection with this, but I've noticed it happen often after reasonably brisk acceleration. If I putt around it rarely seems to happen, but when I accelerate even, say, 1/2 throttle, then coming to a stop at THAT point is when it seems most common. But I'm not sure on this.