New headers on YJ, now problem

[67bbc]

1064870

I just installed a pacesetter header on my 91 YJ, 2.5l. Fit and sound good, for a 4cyl. Anyway, having a problem I need help with. The engine now idles around 1500 rpm's and at around 3500 rpm's and above it seems to load-up/stumble/miss bad??? I triple checked to ensure the mountings bolts are tightened on with the supplied gasket and changed the oxygen sensor with the change. I checked for vacuum leaks and replaced some worn vacuum lines. I am not sure what else it could be since I only removed the manifolds. I also changed the MAP, throttle, and crankshaft position sensors with no luck (disconnected and reconnected the battery several times also to reset). Any ideas would be greatly appreciated since I have a emmission test due next month. :-? [addsig]

 

[MudderChuck]

1064875

Most times when I get high idle, it´s turned out to be a vacumn leak, usually the intake. Try unplugging the 02 sensor and seeing if the idle changes. If it doesn´t I´d start looking at other sensors (MAP, dirty contacts at the plug, vacumn line not hooked up correctly).[addsig]

 

[dingus]

1064897

or you could try disconnecting the battery to let the ECU clear itself of codes, then plug it back in and it might recalibrate itself to account for the increase in airflow.[addsig]

 

[duff]

1064898

did you check to see if even just having a headder will fail your emission test? sometimes they'll fail ya if it's apparent the motors been tamperd with. it was the same when i went to get a sticker for my 84 cj . i could'nt put my new weber carb on till after even though it would run better and cleaner because it was'nt " emissions accepted". your headders might fall into that catagory { in mass. anyways} good luck.[addsig]