Lean Misfires at 2700-2800 rpm

[green-lantern]

Originally Posted by 3000hybrid

Have you pressure tested? Sounds like a leak if it is over the entire RPM range.

I have recently but I could do it again. It seems to run good once I get into it but it seems like it might be a little leaner up top than it used to be. mainly I am dealing with this damn hesitation down low. I roll into the throttle and the wide band goes lean and it starts missing or sputtering (whatever) then it will start to kick in and seem to run strong.

this is what I have done so far. fuel filter, checked the fuel pump connections, and changed the spark plugs (they all looked pretty good).


edit: I am thinking about bypassing the SAFC to see how it runs.

[badass3000]

Originally Posted by 3000hybrid

Will your stocker still fit on your custom plenum? If you don't have it I can send you one of my spares for troubleshooting. They all have working sensors. I always keep the important stuff after I part cars just for these cases . PM me here on on FL3S.

Mann, I have watched your video a ton of times and it still sounds like something in the rear valve cover like a collapsed lifter. I think you said you've already checked them though right.

no, the stock TB wont fit on this plenum. Thanks, but I dont need to TS anything on the TB. I beleive its something in the valvecover. I havent opened it up yet, only the front.

Thnks for wathing my vid a ton of times

[DoctorDex]

Prowler/3000hybrid: When I have my idle set to 700 rpm and I turn the steering wheel or turn the AC on/off, the ISC counts go up, but the idle still drops. I have also verified that the ISC is opening how it should by removing the ISC from the throttle body (leaving the harness connected) while turning AC on/off.

I have given up with this problem as it doesn't affect driveability and I prefer the higher idle since I'm using the solid mounts. Thanks for the suggestions though.

[green-lantern]

Originally Posted by DoctorDex

Prowler/3000hybrid: When I have my idle set to 700 rpm and I turn the steering wheel or turn the AC on/off, the ISC counts go up, but the idle still drops. I have also verified that the ISC is opening how it should by removing the ISC from the throttle body (leaving the harness connected) while turning AC on/off.

I have given up with this problem as it doesn't affect driveability and I prefer the higher idle since I'm using the solid mounts. Thanks for the suggestions though.

doc, did you get your other problem fixed yet? I have been reading this thread but I am only on page 11 LOL.

[3000hybrid]

Originally Posted by green-lantern

I have recently but I could do it again. It seems to run good once I get into it but it seems like it might be a little leaner up top than it used to be. mainly I am dealing with this damn hesitation down low. I roll into the throttle and the wide band goes lean and it starts missing or sputtering (whatever) then it will start to kick in and seem to run strong.

this is what I have done so far. fuel filter, checked the fuel pump connections, and changed the spark plugs (they all looked pretty good).


edit: I am thinking about bypassing the SAFC to see how it runs.

Is your car an SL with ECS? IF so disconnect the ECS controller.

[green-lantern]

Originally Posted by 3000hybrid

Is your car an SL with ECS? IF so disconnect the ECS controller.

no its a 95 base with a 1st gen ECU but I don't know what year it is. when I got the ECU I opened it up and it looked great. for all I know it could be a auto zone ecu though.

[DoctorDex]

Originally Posted by green-lantern

doc, did you get your other problem fixed yet? I have been reading this thread but I am only on page 11 LOL.

Still working on it. I'll be installing a new PTU and trying out 3000hybrid's spare ECU in the next couple of weeks.

[ProwlerGT]

Originally Posted by DoctorDex

Prowler/3000hybrid: When I have my idle set to 700 rpm and I turn the steering wheel or turn the AC on/off, the ISC counts go up, but the idle still drops. I have also verified that the ISC is opening how it should by removing the ISC from the throttle body (leaving the harness connected) while turning AC on/off.

I have given up with this problem as it doesn't affect driveability and I prefer the higher idle since I'm using the solid mounts. Thanks for the suggestions though.

Well the good is that your IAC is working as you've verified.

The useless though... having the IAC on at all with that higher idle serves no purpose. You could probably make a IAC block-off plate with an aluminum can and some gasket maker or cut out a hard piece of metal and do it too that way you could just reuse the IAC gasket that is already in place on the TB.

The bad is it sounds to me like you definitely have a vac leak "when the tb plate moves". For RPMs to drop as the IAC counts go up could mean the leak is at the IAC gasket, IAC itself (I don't like the casing of the new revised ones; there's a split in the middle of the black casing), tb shaft o-rings, tb gasket, fiav, etc....

[DoctorDex]

Installed the new PTU today and it didn't fix the missing problem. However, the stuttering (when revving gradually in neutral) _seems_ to have improved, but I'll give it some time before I jump to any conclusions.

As far as my crazy ISC is concerned it seems to have a mind of its own. Today I was testing the ISC and I noticed that when I turn the AC on the counts go down and when I turn it off they go up. This is completely opposite of how it should be and this is a different result than what I had found before. WTF? I swear this car is possessed.

[markoverclock]

aem group buy.