Weak start (Page 1/1) TheDigitalAlchemist JUN 23, 07:24 AM 86 2.8 Auto 65k miles . Car has started right up strongly until a few days ago. Now, it starts, but the rpm’s go down immediately and the car seems like it is going to stall. It doesn’t, the rpm’s pick back up and then it is fine. Idle doesn’t “wander” Any idea as to what might cause this sudden change? armos JUN 24, 04:48 AM Perhaps an EGR leak - it would struggle to idle until the ECM opens the IAC further to compensate. When the engine starts and you release the key, the cold start injector (CSI) stops adding any fuel, and the port injectors take over all the fueling. The CSI is not controlled by the ECM, but the port injectors are. So it seems one possibility is that you're not getting enough fuel from the (computer controlled) port injectors during start. Then after it stumbles low enough, the ECM is making some correction. One explanation could be a bad sensor reading, such as if the coolant temperature sensor is reading higher than correct temperature, so the ECM tries to start too lean. You won't get a trouble code for sensors unless they're so far out that the readings are ridiculous - the ECM is fairly dumb about this. If you had a weak fuel pump, maybe that could also cause an initial lean condition, but if it was bad enough to be noticeable at startup I think you'd notice an issue while driving. I've only had a bad fuel pump once, and the symptom I remember was stumbling at initial acceleration, not the starting issue you describe, but that was a TBI 4cyl. Fuel pump relay? - if this has failed, then the fuel pump won't activate until the oil pressure sender detects enough pressure. I don't know if residual pressure in the lines would be enough to start the engine before the pump has turned back on. Perhaps bad relay combined with flakiness in the oil pressure sender could conspire to act like this. You could try checking fuel pressure during startup and watch to see if it's acting up when the idle does. When you turn on the key, you should hear the fuel pump prime. If not the fuel pump relay is suspect. When you bump the starter for an instant and immediately release, you should hear the fuel pump run again. If the relay is good but this doesn't happen, the pickup coil is suspect. I don't know if a glitchy pickup coil would cause your symptoms. TheDigitalAlchemist JUN 25, 04:13 PM Thanks for the reply, it only does this the first time I start it, it’s fine after that. 🤔