Car's missing-I mucked something up.
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Joined: Oct 2002
Posts: 10
From: Idaho
Car's missing-I mucked something up.
Hi folks,
I was wondering if anyone might be able to recommend a course of action for my car. It's a '93 A4 with 74k miles with some basic mods: SLP CAI, PCMforless tune, hooker super comp cat-back, carsound cat, 160F thermostat, TB bypass, MSD coil and taylor wires.
Basically, what happened is I did a bunch of work this weekend, putting the PCM chip and 160 stat back in (I'd taken them out for the winter), cleaned and oiled the K&N's, and changed 6 of plugs with new NGK Tr55 iridiums (gapped to .050). With the number 2 and 8 plugs, and took them to a local shop and payed them $50 to replace those 2 (yeah, I have big ham hands and was getting frustrated by this time).
The shop calls me to let me know they're done, and wants to know if I want them to troubleshoot the missing and stumbling. "Missing and stumbling? My car doesn't miss and stumble". Well, it does now. I take the car home, and start poking around. It's barely driveable on the trip home. Horrible missing, backfiring, and surging. Poking around a little bit, I find where number 8 wire goes into the opti is corroded (maybe from my thermostat swap?) badly. Cleaning it up, I get rid of a lot of the problem, but there's still trouble.
Now, after that, here's my symptoms:
-Car pulls strong as ever above 3500 rpm
-Idle is very rough, surges.
-below 3500, the car stumbles, surges, and makes little power, even pedal to the metal. As the high RPM's come, everything is suddenly happy.
Some history:
-The wires, cat, and O2 sensors only have about 15k miles on them. The coil has maybe 25k on it, the plugs are brand new. Fuel filter changed about 10k ago. Opti is the original. I've gotten it wet 2 times before, and got lucky both times (car would miss horribly at high RPM for about 24 hours, then magically "healed itself".
So I'm thinking any of the following:
-I got the opti wet again, and it's finally toast.
-EGR sticking open?
-The shop did something grossly wrong with plugs 2 and 8.
-I got a plug wire burned against an exhaust manifold, or cut by the fan belt (yes, I did that once before). For what it's worth, running it in the dark, I don't see any sparks.
-Something totally different I haven't considered.
Anyone got any thoughts for me before I just start easter-egging with expensive parts? Any help would be appreciated.
Thanks guys.
I was wondering if anyone might be able to recommend a course of action for my car. It's a '93 A4 with 74k miles with some basic mods: SLP CAI, PCMforless tune, hooker super comp cat-back, carsound cat, 160F thermostat, TB bypass, MSD coil and taylor wires.
Basically, what happened is I did a bunch of work this weekend, putting the PCM chip and 160 stat back in (I'd taken them out for the winter), cleaned and oiled the K&N's, and changed 6 of plugs with new NGK Tr55 iridiums (gapped to .050). With the number 2 and 8 plugs, and took them to a local shop and payed them $50 to replace those 2 (yeah, I have big ham hands and was getting frustrated by this time).
The shop calls me to let me know they're done, and wants to know if I want them to troubleshoot the missing and stumbling. "Missing and stumbling? My car doesn't miss and stumble". Well, it does now. I take the car home, and start poking around. It's barely driveable on the trip home. Horrible missing, backfiring, and surging. Poking around a little bit, I find where number 8 wire goes into the opti is corroded (maybe from my thermostat swap?) badly. Cleaning it up, I get rid of a lot of the problem, but there's still trouble.
Now, after that, here's my symptoms:
-Car pulls strong as ever above 3500 rpm
-Idle is very rough, surges.
-below 3500, the car stumbles, surges, and makes little power, even pedal to the metal. As the high RPM's come, everything is suddenly happy.
Some history:
-The wires, cat, and O2 sensors only have about 15k miles on them. The coil has maybe 25k on it, the plugs are brand new. Fuel filter changed about 10k ago. Opti is the original. I've gotten it wet 2 times before, and got lucky both times (car would miss horribly at high RPM for about 24 hours, then magically "healed itself".
So I'm thinking any of the following:
-I got the opti wet again, and it's finally toast.
-EGR sticking open?
-The shop did something grossly wrong with plugs 2 and 8.
-I got a plug wire burned against an exhaust manifold, or cut by the fan belt (yes, I did that once before). For what it's worth, running it in the dark, I don't see any sparks.
-Something totally different I haven't considered.
Anyone got any thoughts for me before I just start easter-egging with expensive parts? Any help would be appreciated.
Thanks guys.
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