While driving my car on the interstate about a week ago, driving nice and smooth, not boosting at all, out of no where the car started to jump almost. I dont know quite how to describe it, but it only happend when I gave it gas, but it would jump violently, calm down, do it again. It would be fine for a mile or so then start up again. I looked down at the blinkity A/F gauge and all the red was lit up. When I took my foot off of the gas, the entire gauge blacked out, like it wasn't turned on. When I hit WOT, it would sometimes show Stoich, or half stoich half rich, but it was never 3 or 4 LED's lit up, it would be about 10. I pulled over, seemed to idle OK, nothing seemed wrong under the hood. I've had the turbo in for about 600miles or so, and since day one I've had a CEL, code 21 which is O2 sensor. Checked it again and its not flashing any other codes. I talked a friend of mine, also with a RS-T, and he said it sounds like its misfiring and to check the wires and coil pack. The coil pack is about 6 months old, nothing fancy just a stock coil pack and the wires are Magnacore race wires, also about 6 months old. I wouldn't think there would be a problem there. Spark plugs are NGK Iridiums. Could the o2 sensor cause this problem? I'm thinking it might be because of the a/f gauge having a seizure and the CEL. I know I'm not running lean because of my FP gauge. Also I'm only boosting 5lbs. I just got back from being out of town and haven't driven my car yet in a week, but I'm getting ready to go get it. So my brothers....what could it be???? TIA!

1996 Mitsubishi Eclipse RS - Sold
1992 Eagle Talon TSI AWD
1999 Dodge Ram 2500 4x4

UPDATE: Just took car around the block, running very rough, when it's sitting at idle you can hear it surging in the exhaust, also it is now flashing CEL 51 and 21, saying running lean and bad o2. Fuel pressure is holding a steady 57-60psi the whole time so I know its not running lean, could a bad o2 cause all of this? Please help asap! TIA!

1996 Mitsubishi Eclipse RS - Sold
1992 Eagle Talon TSI AWD
1999 Dodge Ram 2500 4x4

Yes, Replace your front o2 sensor. Also check your A/F guage wiring. A bad ground can cause that too. I actually had the exact same issue as you a little while ago. I replaced the o2 sensor and checked the wiring to the A/F guage....all good but the problem persisted. On a whim I ripped the A/F guage out and the car ran fine...pooched gauge.

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~Chris
03 SRT-4

I figured it was the o2 sensor, everything seemed to be pointing to that. Is there any chain store (advanced auto, car quest, autozone, etc) that sells a factory replacement o2? I heard the bosch ones suck and I dont feel like splicing wires if I dont have to. I'll also check the a/f gauge. Right now its spliced into the ground for the cig lighter, thanks for the help.

1996 Mitsubishi Eclipse RS - Sold
1992 Eagle Talon TSI AWD
1999 Dodge Ram 2500 4x4

Replaced the o2, ran fine for about 30mins on the interstate then started hesitating and jumping again. A/F gauge still acting screwy. I took it to a friend of mine, we checked all the plugs and wires, didn't see any. I mentioned to him what uber said and we checked the o2 sensor wire and sure enough the wire had melted up against a line behind the TB. Moved it away and the gauge was fine, touched it to the metal and it screwed up the gauge. I repositioned it and taped the wire up, drove fine on the way home. CEL came up for running lean but fuel pressure was pretty low, around 38psi so I believe thats what that CEL is from. Any other input would be apprechiated. Thanks.

1996 Mitsubishi Eclipse RS - Sold
1992 Eagle Talon TSI AWD
1999 Dodge Ram 2500 4x4

Choose a different ground for your a/f guage...there is a nice bolt you can use in the foot wheel on the driver side. right under neath that lil fuse box

__________________________________________
~Chris
03 SRT-4

57-60 psi is a bit too much fuel pressure too. For stock size injectors, you need around 47 psi. That is stock rated fuel pressure. 45-50 is allowable. If you are truely running lean with that mnuch fuel pressure, than something else is wrong. Check to see what your spark plugs look like. Then ceramic insulator should be a tanish/white color. Pure white is a bit lean, and very dark grey to black, is too rich

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)