large problem and im stumped

[iiviasterp]

i recently installed a pacesetter header and after the install i have run into a fairly large problem. under 3,000 rpm's the engine sputters and hesitates badly on exceleration, but as soon as it clears around 3200, it runs like a champ. also, when i cruise at a certain speed for a few minutes the check engine light comes on, and i no longer have the sputtering under 3000. me and my friends thought it could be the plugs or the 02 sensors, we replaced them and i still have the problem....... im lost.... can anyone help???? i also forgot to mention that along with the header i have a freeflo cat also.

[1988starter]

Switch your O2 plug sensor wires so it is white to green and green to white.

[MoonScryer]

And no, he is not kidding, switch them.

[1988starter]

Hey MoonScryer1 what do you think of your msd box I love my 6 AL but I was thinking of some irridium plugs for it.

[Bobs89LXi]

If the check engine light lights, check the code to see what it is. The ECU will store the code in memory until the power is removed from it, either when the battery is disconnected or the ECU fuse is removed. There is an LED on the ECU that will flash a certain number or times, pause, and repeat. The number of flashes is the code which indicates the problem. There is a thread in the FAQ section showing what the codes are.

I agree that it could be the O2 sensor. I had the same symptoms when mine died on me. Check out the ECU codes, then reset it. The best way is to remove the ECU fuse for approx. 2 minuites. You can also disconnect the battery but it is a pain in the butt if you have a head units with a bunch of presets on it. You'll end up having to reset them all again. Good luck.