P1399 Random misfire code after test pipe install?
12-21-2011, 12:47 PM
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P1399 Random misfire code after test pipe install?
I've been reading everything about these misfire codes but haven't seen anyone else with my situation. Could just be a coincidence. Any advice/info would be greatly appreciated.
I have a completely stock 2002 s2000. I installed an Invidia 70mm test pipe a week ago. I screwed the O2 sensor straight into the test pipe without the non-fouler CEL fix, and as expected I got a check engine light pretty soon after the install. Haven't had time to drill out a spark plug non-fouler, so I drove for a few days with the CEL on. Then last night the car started running really rough. Checked the codes this morning and in addition to the rear O2 sensor code, I had p1399 random cylinder misfire.
I took the test pipe off and put the cat back in this morning and cleared the codes. The car ran ok for about 20 minutes, then started running rough again and the p1399 code came back.
Could the test pipe have caused this somehow? I was under the impression the ecu runs off the upstream O2 sensor only, and that the rear is only used to check that the cat is working properly. So the ecu shouldn't have changed anything based on the lack of the cat.
I'm 190 miles into this tank of gas and I think it's been running roughly about that amount of time, so that is a possibility. I'm having a compression test done tomorrow to be safe though.
I have a completely stock 2002 s2000. I installed an Invidia 70mm test pipe a week ago. I screwed the O2 sensor straight into the test pipe without the non-fouler CEL fix, and as expected I got a check engine light pretty soon after the install. Haven't had time to drill out a spark plug non-fouler, so I drove for a few days with the CEL on. Then last night the car started running really rough. Checked the codes this morning and in addition to the rear O2 sensor code, I had p1399 random cylinder misfire.
I took the test pipe off and put the cat back in this morning and cleared the codes. The car ran ok for about 20 minutes, then started running rough again and the p1399 code came back.
Could the test pipe have caused this somehow? I was under the impression the ecu runs off the upstream O2 sensor only, and that the rear is only used to check that the cat is working properly. So the ecu shouldn't have changed anything based on the lack of the cat.
I'm 190 miles into this tank of gas and I think it's been running roughly about that amount of time, so that is a possibility. I'm having a compression test done tomorrow to be safe though.
12-22-2011, 01:56 PM
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I've been reading everything about these misfire codes but haven't seen anyone else with my situation. Could just be a coincidence. Any advice/info would be greatly appreciated.
I have a completely stock 2002 s2000. I installed an Invidia 70mm test pipe a week ago. I screwed the O2 sensor straight into the test pipe without the non-fouler CEL fix, and as expected I got a check engine light pretty soon after the install. Haven't had time to drill out a spark plug non-fouler, so I drove for a few days with the CEL on. Then last night the car started running really rough. Checked the codes this morning and in addition to the rear O2 sensor code, I had p1399 random cylinder misfire.
I took the test pipe off and put the cat back in this morning and cleared the codes. The car ran ok for about 20 minutes, then started running rough again and the p1399 code came back.
Could the test pipe have caused this somehow? I was under the impression the ecu runs off the upstream O2 sensor only, and that the rear is only used to check that the cat is working properly. So the ecu shouldn't have changed anything based on the lack of the cat.
I'm 190 miles into this tank of gas and I think it's been running roughly about that amount of time, so that is a possibility. I'm having a compression test done tomorrow to be safe though.
I have a completely stock 2002 s2000. I installed an Invidia 70mm test pipe a week ago. I screwed the O2 sensor straight into the test pipe without the non-fouler CEL fix, and as expected I got a check engine light pretty soon after the install. Haven't had time to drill out a spark plug non-fouler, so I drove for a few days with the CEL on. Then last night the car started running really rough. Checked the codes this morning and in addition to the rear O2 sensor code, I had p1399 random cylinder misfire.
I took the test pipe off and put the cat back in this morning and cleared the codes. The car ran ok for about 20 minutes, then started running rough again and the p1399 code came back.
Could the test pipe have caused this somehow? I was under the impression the ecu runs off the upstream O2 sensor only, and that the rear is only used to check that the cat is working properly. So the ecu shouldn't have changed anything based on the lack of the cat.
I'm 190 miles into this tank of gas and I think it's been running roughly about that amount of time, so that is a possibility. I'm having a compression test done tomorrow to be safe though.
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