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When stopped at a stop sign or light for a longer time the car will gain less than 100 rpm’s and the check engine light goes on. No idea what it could be.
When stopped at a stop sign or light for a longer time the car will gain less than 100 rpm’s and the check engine light goes on. No idea what it could be.
this does not always happen but on most drives it did at some point. I know at a time there was a month where I never noticed it.
Yep, could be iac valve too. I was just stating it could be a simple problem. Could also be air leak at throttle shaft, imbalanced throttle bores, dirty throttle plates, failing O2 sensor, erratic fuel pressure, failing tps. GM diag flow charts are really good for their old OBD1 systems. I would start with the simple stuff first. When idle is low either flow propane or flammable brake clean anywhere vacuum flows through. Failing that , check condition of throttle plates. If really dirty, clean and retest. Do ecm reset and let it relearn idle. If idle still low then deeper diag. A scan tool is very helpful but almost all testing can be done with a multimeter and back probes on these old dogs. GM has charts that show proper voltages from sensors at certain temps and conditions. Hopefully you won’t need to go too far in depth but these are some pretty simple systems.
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
First thing is get a 84 GM service manual, but to shortcut that, here is your starting point and what you need to check right now...right out of my 84 GM manual. GL
Last edited by Buccaneer; Jan 9, 2024 at 11:31 AM.
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
One other thing. The 84 corvette wiring diagrams is a separate manual. The 82 corvette has everything in one book, the 84 does not. You may want to order this as well. 84 corvette electrical supplemental
