Put a set of Pacesetters and a TD setup on this weekend. The car hesitates at low speeds / rpm's, and wants to die when idling. At a stop, the rpm's fall below 500 and go down to where it just almost dies out, then the rpm's come back up a little. Then it goes through it all over again. I have to sit with it idling for a couple of minutes before it figures out where it's idle speed needs to be. Once it gets there, it is smooth. Once I start going, I can feel it really hesitating at times. I can feel the hesitation when I am also just cruising, and not even on the throttle.

I'm throwing all kinds of codes, mostly for the EGR and AIR that I took off the car. I'm also throwing P0751, which has to do with a shift solenoid, but that was there before the install.

After the install, I thought I had pulled all the relays and fuses for the AIR system. Apparently I hadn't, as I found a third one after the drive tonight. I cleared the codes, and hopefully that last fuse will take care of the AIR codes.

As far as the idle and hesitation, is this just something that the computer will have to relearn, or is something else going on? I checked all the plug wires that I could reach and they're fine. This weekend I'll get to the others on the pass. side.

I know everyone is going to chime in and say to check the plug wires, and I know that. The thing that makes me think it might be something else is the problem with the idle. Also, if it were an issue with the wires not being on tight, then I would really feel it at the higher rpm's, right? The engine runs great at higher rpm's; no missing or hesitation. That's mostly below 3,000 rpms.

Oh yeah, and I also changed the plugs and gapped them to .053 (If it makes any difference.)

Thanks,
-Marc

 

have you run it though a drive cycle? https://ls1tech.com/forums/general-maintenance-repairs/442811-drive-cycle.html

what about your rear o2's? sims or deletes?
i highly doubt the plugs have anything to do with it.

what are you other mods?

 

O2 sensors?

Do you have tuning software or just a code scanner?

 

Never heard of a drive cycle. I'm going to read about it as soon as I post this reply.
Yeah, got O2 sims for the rear, and hooked up the fronts with extensions and everything. Other mods are: 3200-3400 stall converter, B&M supercooler, 3.73's, FTRA, lid, 180 deg t-stat, uhhh....... I think that's all the performance stuff other than suspension and whatnot.

 

no tuning software; just a scanner. front O2 sensors are hooked up, sims in the back.

 

I'll do the drive cycle tomorrow. LT's + TD's + a couple toddies = Po-Po.

 

you probably just broke a plug wire. get someone to scan your car and see what cylinder is missfiring.

 

A good tune will set you straight.

 

BTW it could be an internal break so visually the plug wire would still look ok.

 

I spoke with one of the sponsors about lining up a tune, but they recommended that with just the exhaust I would be ok without a tune. They said I would really need one once I did heads / cam.
Hopefully it is just a wire or plug problem. I'm changing out my TA bushing this weekend, so while I'm dirty, I'll check the rest of the plug wires. If I don't find anything, I'll pull all the plugs and look at them closely. What should I be looking for in particular? Just cracked porcelin?

 

I hate to say it, but I agree with the plug wire/o2 sensor hypothesis. My plug wires were all on after my first header install, but one worked loose on the test drive. I had hesitation and codes just like you described. Good luck!

 

Ok a flashing SES light is a definete misfire on one or more cylinders, loose connection or cracked porcelin could be the reason.

 

If it is misfiring then the check engine light will flash, if it is doing this get it scanned, whichever cylinder is not firing then thats the plug/wire you need to look at.

 

If your're having the codes tuned out for AIR/EGR, go ahead and have the rear O2 sensors tuned out as well. You will be able to sell your O2 sims as you will no longer need them.

 

The SES light isn't flashing, and there aren't any codes being thrown for misfires. Maybe it'll show up after I do the drive cycle this evening after I get home from work.
If it was a problem with the plugs or wires, wouldn't it really be bad at the higher rpm's?

 

you couold have a bad 02 sensor..after all you did just put headers in and the first time you fire it up it burns all the chemicals off and such..it happend to me.only i didn't figure it out till after i spent all the money and time to replace all the plugs and wires..and did you buy the good extentions for the front 02's or use the ones pacesetter sends..if you used thiers maybee your not getting a good connection..the one that was bad on my car was pegged wide open so it would flood out the 4 cylanders and at idle would do the same but at WOT it didn't matter and ran like a champ...

 

Check for exhast leaks. If air gets in the exhast the AFR that the O2 will reads will be off. U may have to look hard for leak. Plugs, wires, bad O2, or leak I bet.

 

Going to take it for a drive and do the drive cycle in a little bit. I used the good extensions, not the ones from Pacesetter. If I want to swap the O2 sensors, can I put the old rear ones in up front, or are they different?

Update: Checked all the plug wires; they're all on tight. Took it for a drive, and the check engine light started flashing. Came back and scanned it. Sure enough - P0300 - multiple / random misfires detected. I'm assuming this pretty much narrows it down to the actual plugs, right?
I couldn't do a complete drive cycle b/c of all the traffic right now. I'll do that later. I hope that will narrow down which cylinders are having the misfires.
Thoughts, anyone?

 

definately plugs or wires,did you remove your coil packs when you did this? maybe something is wrong with one of them but i bet its a plug/wire

 

Just finished with the drive cycle. It is cylinder 5 that is misfiring, so I pulled the plug. I don't see any cracks in the porcelan. The curved part of the plug is white. It doesn't look damaged in any way. Is there a way to check it, or should I just go and buy another one?