I have a 90 L98 Corvette with a rough idle, I am not a mechanic by trade and do most my own work, IAC counts drop to 0 when warm, engine vacuum is at 16hg which is normal for the aftermarket cam that is installed. Things I have done so far is check fuel pressure, leak down test, injectors are about 6 months old, I have checked the ignition system and cant find anything wrong and no codes, The original motor had the same rough idle. I replaced most the sensors with the new build IAC valve, TPS, MAP, and 02 sensor with all new pig tails. The car itself has 190K on it and I believe it is a vacuum leak but cant find any. Thanks For any help.
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