We just put pacesetter LTs on my car on a open off road Y pipe, Car runs great at high RPM, but at low rpm (1000-2000) the car stumbles like nuts so much that the car jerks back and forth. For the extenders we used the wire included with the pacesetters to make our own, but we didn't use the crappy butt connectors included, we got some 18 gauge male/female connectors and soldered them together to make sure nothing came loose. Also, there is no SES light, and it does not seem to do this in 6th gear.

any ideas?

 

I was wrong, I just went out and drove it, and it does do it quite badly in all gears, even 6th.

 

Sounds like you're on the right track, I'd suspect either the O2 extension or a plug wire against a header tube somewhere. I know people do it all the time, but the GM manual says not to solder on the O2's because you can disturb the fresh air feed in the sleeve. Worst case you'll need 2 new O2's and some real extensions. Do the header instructions have you modify the O2 side, or the car side of the harness?

 

Make sure you didn't burn a spark plug wire too.

 

I checked them.

 

the pacesetter instructions said to cut the O2 sensor wires in the center of the connector and O2, then apply the extension wire and solder them together.

 

does it pop with light throttle below 2k rpm?

when i installed my headers some of the spark plugs were a bit tricky to install, it turned out i screwed up the gapping on 1 of my spark plugs.

caused a low rpm popping sound and of course a miss

good luck

 

hard to tell, because its running on an open Y-Pipe it pops a lot while down shifting or lettign off the throttle, but I dont think it ever does it while accelerating

 

Alright, its not the O2s or extensions, replaced them with a friends. Also it does it as soon as I start the car, and the pcm ingores the O2s at that point. I would like to mention that half the time I have a hard time starting the car. It takes 2-3 seconds longer then usual and then it sputters real bad once it fires up. And after letting it warm up for 10-15 seconds. pull out of the driveway it almost dies on me like im not giving it enough gas (this is only when the engine is cold)
Another thign just came to mind, when we changed the headers we also changed the plugs. Because I will be getting nitrous soon we put in autolite 104 with a 0.035 gap.

 

I know it sounds stupid but check to make sure that you don't have a plug wire crossed.

I personally am notorious for crossing 6 & 8 - car is hard to start and runs like crap. Just something to check. I would think that you'd know this right away tho - it's very obvious.

 

WIRES dude May be a plug, but my money is on the wires, even if you cant "see" anything wrong with them. They may be cracked on the inside . Same thing happened to myself after my header install. HTH

 

wouldnt wires cause a constant miss, high, and low?

 

Nope. When my wires were f**ked, under 2k rpm the car would buck like MAD, especially in 5th-6th.I was doubting it would be that as well, cause they "looked" fine on the outside, but i had just pulled/reinstalled them while doing the headers, so 1 or a few must have busted on the inside.
When changed, everything was hunky dory again

I cant recall now ( cause this was 4 years ago), but i suppose there must have been some power loss at the upper rpm's as well like you state, but nowhere near as much as under 2k..................

I'd start there...hth

 

The car feels over all weaker to me, although WOT does not miss....it just doesnt feel like it's pulling as hard.

 

we just pulled plug 1 to inspect it last night, for some reason the gap on that plug had closed from 035 to 029, im hoping this is my problem, regapping to 40 tonight.