When i start my engine when its cold, it will idle around 1200-1500 rpm, but will give me a really loud hiss and then go away and the idle will drop about 3-400 rpm, then the hiss will come back and idle back up, did a little tweaking, set the idle as per the instructions in the tech article. after taking it for about a 5 minute drive i parked it, seemed to idle smoother, but would kind of 'studder' every now and then, then i figured id see what it did when i held it at a higher rpm, so i held it at 1500 and it would bounce around a little, then i held it at 2k and it did the same thing.

I know the TPS needs to be replaced as when i put the volt meter on it it would have a spot where the volt meter would say overload(about 3/4-7/8 throttle) Could that possibly have anything to do with this problem?

 

I had a smiliar problem. Did you recently change your cap and rotor???

If not, than take it out and check in what conditon it is. That hissing is usual when warming up and in open loop. However, if you don't have an open element than it might be a problem. I had a hiss because my cap wasn't sitting right. Check it and clean it, or replace it. Once you're done make sure you get that distributor screwed down right.

Good luck.

 

Deffinantly not the cap, just replaced it, i know the hissing is normal, but it should be hissing then stopping and then hissing agian.

 

Possibly. Thats indicative of a dead spot in the tps where one of the resistive traces has worn away. Not a bad idea for a new unit.

The hiss is the stall saver. The IAC is commanded to rapidly open to prevent the engine from stalling. From the sound of it this only really happens when the ecm is in open loop idle. Its possibly caused by a bad IAC, too low of a min air adjustment, a miss, or some other issue with the engine that causes a low idle

 

engine doesnt idle low though, when warm and in gear, it idles at aprox 700 rpm.