1992 Cadillac Deville stalling

It takes like 3 tries to start, it makes a tapping/knocking noise when it fails to start.

It starts, but I have to give it a little gas. What do u think would make the tapping noise, while its not running?

Ok. I just figured out the tapping sound. It's the metal peg sticking out in front of the ISC motor near the throttle. Why would it be tapping?

It's not even a month old.

Brand new. I think the notched end maybe loose. And that might be why its dying in idle when I first start it up, and its throwing the e30 code (isc out of range). How do u tighten it?

I figured it out. The notched end that presses up against the two metal cables that are attached to the throttle wasn't screwed out far enough. This is what kept the car from running fluently, and is why it died. I tinkered with it, unscrewing it little by little until it started, and ran without stalling or hesitation. But after I drove it for 50 miles, as I turned it off, it still did the tapping thing? I don't know why it would do this.

It stills runs a little rough when I first start driving. But it doesn't die after I fire it up. That's reassuring. But, it still throws the service engine soon, and service vehicle soon lights intermittently. Soo. I think it may be my bcm goin out.

Might be the bcm, or it might be some kind of sensor. I know I have done alot of trouble shooting on my 87 seville and found that if I unplug both my temp sensors the idle speed controller goes nuts. Its basically all based off of the temperature of the engine so that could explain why it runs rough at first, the engine is cold and the sensors may be worn and out of sync, but then as it heats up runs better because it either gets a better reading or is just stuck in the general position it needs to be for that temp

As far as adjustments go though, I wouldnt think it would need to be adjusted really. The throttle position sensor would be able to make the necessary adjustments if it was out of whack. If I had to guess, which obviously I do, id say temp sensors or one of the computer modules, see if unplugging both temp sensors causes any real change in its operation, if not then that is probably your issue, if it does change well it could still be them they might just only be partially functional

Oh yea, and check your alternator output. Just not at an auto parts store their machines have never helped me one bit it always comes out good regardless. If you arent getting about 13-14 volts out of it you have an alternator issue which could cause an incorrect reading of the sensors. They are based on resistance if I remember correctly so if the voltage going in isnt right the signal coming out is off

Thanks. So I'll try unplugging the temp sensors. How many are there, and where are they located?

"both" lol. Gotcha. But locating, I'm kinda lost on that one.

There should be two, and I cant necessarily tell you exact locations its a different engine but that info shouldnt be too difficult to come across with some google searching or if someone with the same engine can tell you. I have the infamous ht4100 in my current cadillac and I havent really gotten into my new one yet but that has a 4.9

They should be somewhere on the intake manifold, there are these bolt looking things that screw in with wires coming out, those are the sensors, one should be near the spot where the top hose to the radiator hits the engine, the other I cant really recall but once you find one you should be able to identify the other