I have a 1994 LT1 Coupe, automatic with 130k miles on it, (daily driver), it ran fine up until about 3 months ago when I ignorantly pressure washed the engine. I later found out that the Opti-Sparc distributor is sensitive to moisture, so I won't do that again! However, after a few days it ran fine again with one exception, a slight and occaisional miss at idle, which continues to this day.

After driving it like that for a while I noticed that performance was way off, or at least it seemed like it was, and it would hesitate at half throttle to the point that it would actually back-fire during acceleration when the engine was cold. so I took it to the dealer, told them what I did, what it was doing, and said fix it. I expected them to replace the Opti-Sparc, but they said it was in good shape and proceeded to replace the fuel filter and spark plugs, and cleaned and flushed the fuel system, they said it was pretty dirty.

When I got it back from the dealer I noticed a definate improvement in performance, most notable at WOT. However, all symtoms were still present, and are still to this day. So I took it uppon myself to replace the Opti-Spark, and plug wires. It deffinately runs better, but the hesitation is still there and so is the occasional miss at idle. I have also put a high performance Moroso Pro coil on it since then. I ordered it a whild back and had intended to put it on after the other problems were solved but tried it just for grins anyway, and it made no difference.

I've had the car for 1 1/2 yrs. and have had to replace one of the O2 sensors, and the EGR valve. Other than that just routine maintenance.

I also forgot to mention that the hesitation is still there even after the engin warms up. However it is almost not noticable. And, the hesitation occurs well after off-idle and sometime just after the shift to 2nd.

Any Ideas?

Thanks in advance,

Mike