I have a 95 Tahoe with a TBI 350. I rebuilt this engine earlier this year due to pitted cylinders. Since, the rebuild I haven't been able to get it to run quite right. It runs fairly well once warmed up. However, on cold start it idles terribly. During the rebuild I used an RV cam, which was supposed to be mild enough to work with the OE chip. During cold start the engine acts as if it's flooding with a miss and vacuum is low. I fairly certain it is. Once, I apply a little throttle it goes into closed loop and clears up. Once the engine warms up and the engine goes into closed loop the vacuum increases to normal range. The IAC or ECM is a little suspect. The IAC will not zero out when the OBD port is jumped. However, I can see it working on the scanner.
Things I know.
Map Sensor -good
ECT(Coolant temp sensor) -good
EGR Sol and Valve - good
Distributor Assembly - Replaced
Plug Wires- Replaced
Base Timing- Set to 0 w/ wire unplugged
Throttle Body/Fuel Pressure regulator - Rebuilt
Things I know.
Map Sensor -good
ECT(Coolant temp sensor) -good
EGR Sol and Valve - good
Distributor Assembly - Replaced
Plug Wires- Replaced
Base Timing- Set to 0 w/ wire unplugged
Throttle Body/Fuel Pressure regulator - Rebuilt
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