I've got a low cold idle (650-700 rpm) on my '89 325i that's stumped me, I have no stored codes and essentially all-new everything over the last 6 months. I have a new temp sensor (actually 2, to make sure the first wasn't faulty), ICV valve, spark plugs, TPS sensor, C191 connector, ignition coil, CPS, main/fuel pump/O2 sensor relays, distributor cap/rotor, plug wire loom, and I'm back to running the stock AFM (after reverting from a Miller MAF, and all wiring correctly reverted). I've gone through every vacuum line and potential air leak MANY times over.
Cold start itself is fine, though I typically don't get enough rpm's on start-up to clear the warning lights and have to give it a stab of throttle to clear them. Once the engine warms the idle raises a bit, but just to normal levels, and I'll occasionally get a stumble on cold gear change where the engine almost dies, but again no code is stored.
I'm running a no-name header into a Borla exhaust with a free-flow cat, and at this point it's the only thing I can imagine causing my low idle. Adjusting the idle via the adjustment screw just ends up causing a bouncing idle and not helping cold idle.
Any thoughts?
Cold start itself is fine, though I typically don't get enough rpm's on start-up to clear the warning lights and have to give it a stab of throttle to clear them. Once the engine warms the idle raises a bit, but just to normal levels, and I'll occasionally get a stumble on cold gear change where the engine almost dies, but again no code is stored.
I'm running a no-name header into a Borla exhaust with a free-flow cat, and at this point it's the only thing I can imagine causing my low idle. Adjusting the idle via the adjustment screw just ends up causing a bouncing idle and not helping cold idle.
Any thoughts?
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