When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
When the engine is warm (180+ Degrees) and I let the car sit for 30-60min, the car will fire up normally, but the idle will dip down to about 400-500rpm for a second and then idle normally from there on out. Has anyone else experienced this? I have cleaned both the MAF and Throttle body, checked all intake fittings, and have recently put new intake manifold gaskets which had no impact to this problem before or after. I don't think I have any vacuum leaks either...any help is greatly appreciated!
Normal operations. Your IAC is quickly resetting itself hence the quick drop, then normal. So, every time it happens please just remind yourself that everything is working as designed.
Bill, no IAC on the C5…OP, probably best to find a scan tool and look at some live data to see what’s happening concerning your idle…don’t even want to guess…is this a tuned car ???…idle RPM is controlled by the TAC module.
Bill, no IAC on the C5…OP, probably best to find a scan tool and look at some live data to see what’s happening concerning your idle…don’t even want to guess…is this a tuned car ???…idle RPM is controlled by the TAC module.
Correct, no IAC. Okay, thank you for the suggestion on looking at live data; probably the best route. This is not a tuned car.
Do you know where the TAC module is located...below the PCM...??...pic below...I'd remove the 2 connectors and get some contact cleaner and spray both and then reconnect...make sure there are no bent or spread terminals...I would start there. If no luck and you know how to graph live data with your scan tool while you are trying to replicate the problem I would look at RPM, TPS voltage, MAF, MAP, APP, Load, Fuel Trims and O2 sensors...when you graph notice when that RPM drops and see what other sensors may be affected during the RPM drop. Always a good idea to include your location...you may be a neighbor...there are MANY Corvettes in Southwest Florida.
Warm Start Idle Drop
