Missfire below 4500 RPM's

[Mram76]

i have the same problem the car drive fine but at a stop light it idle rough. it drop about 500 rpm. i change the plugs, wire, tps, and isc. i still having this problem.......by the way have a 99 rs..

[GSTRacerNVUS]

Mine does it too... Even after changing tps, spark plugs + wires, cleaned TB, bored cat. I definately runs a lot better than what it did, but it still idles rough around 600. From what I understand, it isn't even supposed to be that low. Mine didn't go lower than 8 at first when the tps was ajusted by voltage, but about a day later it went back. The guy who gaped my spark plugs does nothing but work on GSTs and Xs, so I'm assuming he knew what he was doing. I could be wrong.

[earlpitts]

nope... no check engine light.... nor does it throw any codes

[RiceRocket18]

guys idle rough at the light could also try look for vacume leaks.

[earlpitts]

I drove the car a bit yesterday. Still with the same missfire/cut-out, I think I'm going to try and change the coil pack. It acts as if the I lose fire for a few seconds then I get it back...maybe this works?????

[GSTRacerNVUS]

Here's a couple of previous threads that might help. I found some info.

http://www.automotiveforums.com/vbul...ght=rough+idle

http://www.automotiveforums.com/vbul...ght=rough+idle

I know they look the same, but they are two different threads, just the same title.

This may help, too.

http://members.shaw.ca/costall/1000Q...otidleverywell

[earlpitts]

OOOO K... I'm not sure how this got turned into a rough idle thread... Im still cutting out below 4.5K changed to coil pack.. still the same thing...I', going to try and clean the injectors now

[earlpitts]

No more ideas to try? Maybe this is more like an enjine surge than a miss.... I can hold the peddle at like 2.5K and the rpms drop like 300 rpms and then bounces back...Ive checked the thottle position sensor and it shows fine... could this be a knock sensor reading a false knock and retarding the timing? ANY help with this is greatly appreciated

THANKS
00

[ashah000]

Is this a AT?

[earlpitts]

No...Its not an AT...its a 5 speed... and yes it does the same thing in all gears.. man this has me puzzled

[RiceRocket18]

ok .... i give up !!.. regapped the plugs, changed the plugs, changed the wires, changed the ISC, adjusted the BISS, spent all afternoon cleaning out throttle body and still misfires like a dick when decelerates!!. i am taking it in. this is not worth my fucking time!.

[WankelTII]

I have the same problem in my base 92 eclipse (1.8L), it miss fires between idle (800-900) and about 4000rpms. Its much much worse when the engine is cold. My car idles fine, but when i give it gas at low rpm in any gear, it will stumble alittle. I dont have any vacuum leaks, no check engine light, i have swaped distributers and caps from another base 92 that i had that didnt have the problem. My dad thinks its a fuel problem, but it is obviously miss firing, and running rich because sometimes it will backfire. I have changed the fuel filter and been running nothing but premium with some injector cleaner (just in case it might be fuel related). I swaped ECUs and plug wires too. When i got the car it was much worse, it had shitty plugs, but i put in bosch 2 prong platinums. I know those plugs arent amazing or anything, but they dont have to be gapped and i wouldnt think they are the problem. I had some bosch 2 prongs in the other car for a while with no problems and when it was time to change them went back to NGKs and could tell no difference. Also my O2 sensor is new. If anyone has any idea what could be causing this please let me know, along with all these other guys who are having the prob

If anyone thinks they need an O2 sensor go to O2sensorsonline.com they are awesome! Got mine from them for $25! Auto zone, advanced, and nappa dont carry a sensor for my car, so it was going to be $251 from mitsu.