So I finally got my Pacesetters and ORY installed and the car runs like crap now.
It starts and idles fine, but as soon as I give it gas it starts to bog and hesitate. I have the EGR hooked up but blocked off the AIR fittings. I haven't removed the AIR system yet but I don't think that it has anything to do with it. I got the O2 sims and extensions on and my SES light didn't come on until I put around 40 or so miles on it.I double checked the plug wires and they seem ok. A friend of mine is coming by with LS1 Edit to check it out, but I'm looking for some ideas in the meantime.

 

Sure you put the O2 sims on the REAR oxygen sensors, NOT the front ones?

 

NotAV8....Don't you mean the opposite ?? fronts are needed...rears aren't and won't affect the engine at all other than the ses light....he's got an ORY pipe also...

 

I had the same thing happen like a month ago. My SES light does not come on every time I drive it. The only thing that I changed were the O2 sensers (Bosch) before it started doing its pouting. I never had this problem before with the stock O2 sensors. The wierd thing is my temp guage will drop to nothing like its not even reading. Unhooking your battery to reset the SES don't do jack. I know gotta chek the connection of the resisters (O2 simms) or buy new O2 sensors soon. I don't drive the car every day. so I just parked it.

 

If you block off the AIR fittings, it will throw a SES code, even if it's still plugged in everywhere else. I'm fairly sure there is a pressure sensor that makes sure it's hooked up by measuring pressure of the air trying to blow down the tube. When I blocked my AIR off, but left the rest of the system on with the tube blowing fresh air into the engine compartment, it still came on.

The car needs a little time to adjust to the changes. My car ran fine after I installed my exhaust, but my buddies needed a couple hundred miles before it came around.

If there is a shop that can edit your car, or your buddy can do it with his, it's best to just delete the AIR/EGR/Rear O2 codes all together. You will save money on buying sims, then pay a shop to do it if they even charge you. MTI charged me $75, which is less than a set of O2 sims should run you.

 

Cracked plug, look very closely at each plug, they can be cracked even if they're straight out of the box

 

egr not sealing up well??? causing a vacum leak

 

Sounds like you forgot to plug your harness back into your engine temp sensor or the sensor is bad. The car will run like **** after about 30 seconds if you don't have it plugged in because the car cold starts in closed loop, then reverts back to open loop where temp readings are NECESSARY to determine stoich AFR.

I forgot to plug mine back in after my second cam swap and it screwed my idle up pretty badly. It's the black connecton on the driver side of the block right in front of the first header primary.

 

I had the same problem when i installed my LT's and it was were the O2"s sensor was installed to far down stream from the motor and the air going across the lower header tubs was cooling down the exhaust and tricking the computer ,by pulling all the fuel from the motor making it think it was running rich (cool is rich & hot is lean) .I rapped the header tubs haft way down to put more heat back into the exhaust and fixed it .My LTFT"s are at -2 .Alot of people says that rapping the tub will cause cracking but I've had mine rapped for over two years now with no problems at all . Take a scan tool and see if your running lean ,before rapping I was +25 and now after rapping -2 .

 

Thanks guys, I've got someone coming over with LS1 Edit to check it out. As stated before, the SES light didn't come on until after I put about 40 miles on it. It starts and idles fine. I took it out last night and put a few more miles on it and it hasn't changed.I don't want to keep driving it and screw up anything else. Thanks for the input!