Low RPM Misfire / Stumble
01-30-2005, 07:34 PM
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Low RPM Misfire / Stumble I am having a low RPM misfire and stumble ever since the cam install. I am running open headers now.. for a while I was having a hard time getting the car to idle.. until I idled up the idle screw and drilled the TB it would just die on startup. Anyways.. the idle is a little more steady now.. but I am having a horrid low RPM misfire... under 50% or more throttle it clears up... and under WOT it just screams. WOt feels perfect....
Was wondering what could cause this.. mind you I am on open headers and was wondering if this would have an effect on how the car's AF ratio was handling itself.. it seems to miss even before the car is warmed up tho.... before it goes into closed loop.. but like I said WOT and 50% or more throttle is fine.. about 3000 rpms seems to be fine...
Was wondering what could cause this.. mind you I am on open headers and was wondering if this would have an effect on how the car's AF ratio was handling itself.. it seems to miss even before the car is warmed up tho.... before it goes into closed loop.. but like I said WOT and 50% or more throttle is fine.. about 3000 rpms seems to be fine...
01-30-2005, 09:14 PM
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is the car tuned? the car will have miss fires at idle from cyl pressure bleeding off. if u are running open headers like that people have had problem with o2's its like a huge exhaust leak cause the o2 can get fresh air, i suggest putting some extensions on the headers and getting a tune.
01-30-2005, 09:19 PM
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Originally Posted by fast98
is the car tuned? the car will have miss fires at idle from cyl pressure bleeding off. if u are running open headers like that people have had problem with o2's its like a huge exhaust leak cause the o2 can get fresh air, i suggest putting some extensions on the headers and getting a tune.
anyone? 
02-01-2005, 12:16 AM
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Originally Posted by WILWAXU
put some exhaust on it.. my guess the O2's are getting fresh air on them (cool), freaking the PCM out.
You should never run a EFI car open headers. You need a minimum of a collect extention tube ~6-8"
You should never run a EFI car open headers. You need a minimum of a collect extention tube ~6-8"
Well.. with my exhaust cut down there are slight extentions on them.. I am guessing 6 inches or so.
