Changed the rear O2 sensor today (code + stumbling)...also hooked up the boost sensor and MAP/Baro switch solenoid valve (code). Both codes are now gone, but they've been replaced by 0701 (Multiple Cylinder Misfire). WTF??? The car's running great, but now this. I...just...can't...win. Anyone have any ideas? The only other codes I have are Evap and EGR related. Thx.

 

So you can't hear or feel the car misfire? Reset it and drive it some more and see if it comes back. All injectors and coil packs plugged in?

 

Yes...all injectors (the front 3 of which are not genuine 3.5 plugs) are plugged in...had to modify those three (as GoalieKeg did on his swap). Coil packs are plugged in as well (unmodified). I'm not kidding when I say that the car appears to be running right. Smooth idle at 650 (slightly more vibration, I'm assuming, because of the ES mounts), excellent power, normal starts, no symptoms of anything wrong (now that I've replaced the rear O2 sensor to get rid of the corresponding code and some stumbling during acceleration). I've read that this code (0701) is possible if a car is running rich (as the 3.5 swap's apparently all do at first). Bottom line...is the car safe to drive? What would the misfire "feel like"? I've never had a car with this problem b4.

 

I'd do what kevlo said reset the ecu and drive around a atleast 200miles to get the computer upto speed so to say.


misfire:it would fill like a interuption in the flow of the engine while driving.sometimes accompanied(sp?) my a backfire

 

OK, I left my battery disconnected all night last night in an attempt to start fresh. I'll drive the car for a bit and see if I encounter any problems. As I mentioned, I'm noticing absolutely nothing right now (knock on thin sheetmetal). I'll post an update soon. In the meantime, any other comments/suggestions would be appreciated. Thx guys.

 

I got that same misfire code a long time ago as well. Sometimes these ECU's through out a false signal. Just as everyone else mentioned, reset ECU and drive. If the car feels strong than most likely it was a false signal.

 

I would reset the computer by the screw on the computer. That will surely reset it. Just move the screw back and forth two times in a row.

 

I went to "Checker Auto Parts", had them run the scan tool and then reset the ECM. For some reason, he couldn't reset P443 (Evap Emissions Control). Anyway, car continues to run beautifully...still getting the flashing CEL, though. It came back within 2 miles or so. Everyone I've spoken with/heard from so far says just to drive the car and see what happens (so long as it continues to run well, that is). I have a great deal of difficulty imagining that any of the coils/plugs/injectors are bad as they all have less than 1,000 miles on them and, as I've mentioned, I don't notice any misfiring/driveability issues...just a slight indication that the car's running a lil' rich. Make way for the SAFC or E-Manage.

 

5th/6th ECU reset is a bit different.

 

This is a 3.5 SWAP.

 

Doesn't the ECU get swapped as well? I could be wrong.

 

It could get swapped but most dont do it.

 

Alright, thanks for the clarification.

 

Yeah use the screw method, not battery.

 

Unplugging the battery resets everything if left long enough, including the fuel trims, basic idle, etc. The screw will just reset the CEL.

 

Update: I hooked up my EVAP today, so now my only codes are 0305 (EGR), 0701 (Friggin' misfire) and 1005 (EGR). Since the car's running great and my EGR will, in all likelihood, never be hooked up, I'm very happy with the way things are. Tomorrow I'll order a VAFC, install and dyno. Hopefully no surprises lurk around the next corner. Of course, we are dealing with cars, aren't we? Thx 4 all your help, guys.