Hi everyone, so I recently had my SES light come on coming back from work one day and immediately noticed the engine stuttering and have sporadic rpms (almost stalling when idle). I had the codes read and it gave me just a P0300 Multiple Misfire Detected. Being that the car has over 100,000 miles on it, I switched out all spark plugs. The problem continued so I had the car on and unplugged each ignition coil to see if one of those were the problem. I found that cylinder 3 (middle on passenger side) was at fault and had it changed. After changing it, I turned it back on and car ran normal but light stayed on. I discounted battery to reset the ecu, however that didn't work. I drove it to work since nothing was visible wrong and after 2 days the SES light went away, but after about 2 hours clicked back on and has stayed on since. I had the codes read again and this time it gave me:

P0300 - Mulitple Misfire Detected
P0507 - Idle Speed Control System RPM Higher Than Expected
P0102 - Mass Airflow Sensor Circuit Low Input
P0507- Idle Speed Control System RPM Higher Than Expected

Side Note-When I checked the coils I didn't test the top left belonging to #5, as it is a PITA to get to and having found that #3 was faulty and car ran normal after I didn't look further into it. Could that be the issue, even though it is running fine and when the previous coil was acting up there was a noticeable difference.

I've listed a few things I changed or tried below if that helps:

1) Replaced all spark plugs
2) Replaced Cylinder 3 Ignition coil
3) Cleaned CAI (Popcharger)
4) Cleaned MAF Sensor
5) Cleaned Throttle Body
6) Turned on with MAF sensor unplugged. (Revs became sporadic in idle instantly, so MAF is working)
7) No noticeable hissing from engine but haven't checked further for vacuum leak

Any ideas?

 

Sorry dude, was responding to the wrong post. Too many open windows.

 

wrong post?

 

Did you clean the Throttle before or after you got the extra DTCs?

 

I cleaned the throttle before the extra DTCs popped up.

 

did you push on the butterfly valves?

 

When i sprayed the throttle body? Yes i did.

 

Then you need to do a throttle re-learn and hope that you didn't damage the throttle to the point where it needs to be replaced. The throttles on the Z are notoriously easy to screw up. Do a search and read about the issues people have had with these things. For future reference, you should never manually adjust a throttle butterfly valve that is electronically controlled without following the FSM procedure EXACTLY as written. It might be a good idea to take your car in to have it properly diagnosed and/or reprogrammed using a factory CONSULT computer.

 

zak knew where i was going with this.