Ok I've checked out everything I can think of to ensure no vacuum leaks. I replaced the plugs with delcos and the wires with accel 300+ (too me awhile to make the boots). I also removed all smog equipment and plugged it all up since I was going to change plugs. I got the car to stay running ONCE with the IAC and MAF disconnected but it hunted from 500-1500 the whole time and right when it was about to die it would rev itself to 1500 again. I tried to adjust the IAC and with the aldl jumpered the little IAC motor never stops making noise - does this mean it's bad? The only other remote possibility for something I could've done wrong is switching the MAT and manifold CTS sensors but aren't they identical anyway? Any help is very much appreciated (and needed!)

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89 Iroc-Z LB9 305 TPI auto 2.73 posi:
3" Dynomax "cat" back,K&N filters, TB bypass, 3" pipe in place of cat, cleaned and flow-matched injectors, 180' thermo, mild ignition mods, synthetic oil, kicker sound system, soon to attempt engine swap...

 

btt

 

First off, the MAT and manifold CTS sensors ARE identical.

As for what's going on with your car, what codes are being thrown? Check your TPS and EGR and make sure they're in good working order. Also check your fuel pressure, and your ECM grounds and connections. I'm not quite sure about the noisy IAC motor, but it doesn't sound right. But, with it disconnected, your ECM should be plugging in it's own preset values. Good luck. - John '89 L98

 

Thanks for the reply. No codes are being set. Fuel pressure is good. The ecm hasn't been touched since the car ran perfectly. I'm beginning to wonder about the IAC since the one time the car stayed running was with the IAC disconnected. I'm gonna tear down the tpi again and inspect the egr, originally I thought maybe I'd forgotten to tighten one of the egr bolts but they look good. I mentioned the CTS since in my Helm manual it lists a faulty CTS reading as a cause under "rough start"...i'm starting to lose my mind here...(who am I kidding, it's been gone for a long time)

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89 Iroc-Z LB9 305 TPI auto 2.73 posi:
3" Dynomax "cat" back,K&N filters, TB bypass, 3" pipe in place of cat, cleaned and flow-matched injectors, 180' thermo, mild ignition mods, synthetic oil, kicker sound system, soon to attempt engine swap...