anybody ever bought a reman opti and it didnt work correctly? i just replaced my opti 12K or so ago, and i am having this problem again....could a bad fuel pump cause a bad hesitation? i noticed i have to crank a while to get it started...let me know

 

wow this thread is long. but anyway... i dont remember if i said to try this in the beggining, but i only read the last page just now. you are having the EXACT problems i used to have. mine even made the EXACT hissing sound your talking about. (btw, that is the iac opening all the way to try and bring the idle up when it stumbles at idle.) it even lasted the same amount of time. it took about 20 minutes to start stubling too. try the ICM cooling mod. all you do is put 3 washers behind the ICM/coil to create a space between it and the head. what was happening to mine was the ICM would get hot (after about 20 minutes of running) and it would act up. we all know electrical components dont like heat. it worked for me, and its free, so give it a shot before doing the opti.

more detailed instructions can be found here.... http://shbox.com/1/4th_gen_tech2.html#ICM_cooling

 

DOh, I just ordered an opti. I already have 1 washer behind the coil. Maybe Ill try a few more and give it a whirl. THanks.

 

yeah, try three. 1 prolly isnt enough space.

 

Just put in a total of 4 washers on each side. Theres a pretty good space in between the head and the coil. Problem still persists. I just want this to be over with . Guess Im putting in a new opti. Any other ideas?

 

yeah I gots the same problem. Changed plugs and wires, had everything checked out all lines were cleaned, fuel pump checked out ok, but no solutions !!!! This is driving me nuts. 93 z28 135000miles, ran great till this happened !!!

 

Looks like we're in the same boat brother, and we're going down. I just got my opti in the mail today and I'm afraid to open it. I know thats not the real problem but I might as well rule it out.

 

could the air pump system cause these problems,

 

Yea, could it be the airpump? I can hear mine when I start the car pretty loudly. Never noticed it before the problem started but never really looked for it.

 

i'm not really sure when it's used but if it's putting either too much air or at the wrong time it seems it could mess with the o2's

 

Well its used right at start up so Its not SUPPOSED to be working while my problem occurs. I am just wondering if its even possible for the air pump, whether its good or bad or malfunctioning to even cause this problem.

 

wouldn't it act the same as an exhaust leak before the o2's , if it was pumping air in after closed loop, i think it's there to help the cats burn cleaner when they're cold and open loop.

 

I'm not sure if its possible for it to be pumping air in after closed loop though, I think if its messed up it just doesnt work at all rather than working when its not supposed to.

And another thing, could this be rocker related at all. I took off my valve covers to get to an exhaust leak a couple months ago. Maybe I inadvertently screwed something up?

 

from my experience, i wouldn't think it's rockers, i think it's sensor related in one way or another... either a bad sensor or wiring to it.
well... if the air pump sys. isn't working right , who's to say how or what it's going to do, what if the asp. valves are leaking, drawing in some air from the the pump

 

my car still acts up under 3000 rpm at times , i don't drive it much and it's coming apart to put the other parts in soon so i didn't try to hard to fix it yet.
i'm going to cap off the air tubes to see if it helps, so... nobody else out there has any input on this