Connor280ZX Posted February 14, 2013 Share Posted February 14, 2013 I thought i was in the clear after i replaced the O2 sensor, and cleaned the AFM, but i was wrong... However, the car did perform great for a few days, then the dreaded misfire came back. It acctually started to backfire through the intake, and at certain times the engine would cut out and it felt and sounded like it was temporarily running on 3 or 4 cylinders. This only happened occasionally, and once i rev it for 5 seconds or so, the car starts to run normal, and i am able to get the car home. Just about 30 mins ago, i replaced the CHTS thinking that this has got to be it since it was totally coated in corrosion and white crusty stuff. I hooked the new one in, started it up and i was dissapointed to see that the car was running just about the same. However, the idle started slowly surging between 900 and 1300 RPM, and would occasionally drop to 500 but wouldnt stall. So pretty much running the same as far as i can tell, havent taken it for a test drive yet. in the past month, the problem has just been getting worse, and i fear that the thing's gonna die somewhere, so i havent really been driving it except for quick runs into town. Heres some specs on my car: 62,600 Miles, 5 speed, N/A Upgrades: PS20 Ignition Coil, MSA Catback exhaust. Parts replaced in past 4 months: Spark Plugs, Plug Wires, Distributor Cap & Rotor, Air Filter, Fuel FIlter, Fuel hoses, Master and slave cylinder, O2 Sensor, CHTS, and the PCV valve. The only other things that i could imagine that could be causing the problem is the AFM, Air Regulator, and the EGR Valve... Or am i wrong? Quote Link to comment Share on other sites More sharing options...
phil280zxt Posted February 16, 2013 Share Posted February 16, 2013 Have you cleaned and reseated the ECU connectors? Quote Link to comment Share on other sites More sharing options...
Connor280ZX Posted February 16, 2013 Author Share Posted February 16, 2013 No, i havent thought of that... Do the connectors get corroded? Quote Link to comment Share on other sites More sharing options...
darkstarrocker Posted February 21, 2013 Share Posted February 21, 2013 Yes, and they're crap connectors to begin with. Buy some Deoxit and clean all the plugs. Quote Link to comment Share on other sites More sharing options...
NewZed Posted February 21, 2013 Share Posted February 21, 2013 Have you measured fuel pressure? Timing? Looked for intake leaks? Can't go wrong with confirming that the basics are right before you get in to the fine details. Quote Link to comment Share on other sites More sharing options...
Connor280ZX Posted February 21, 2013 Author Share Posted February 21, 2013 The ignition was timed about a month ago. It was 10 degrees over advanced, but after the tune it didn't really seem to help. While the car was running I sprayed a bit of WD40 around the gaskets to see if the idle would change, but all of the gaskets seemed to be fine. I haven't checked fuel pressure, but backfiring trough the intake means its running too lean right? Quote Link to comment Share on other sites More sharing options...
Connor280ZX Posted February 28, 2013 Author Share Posted February 28, 2013 Follow up post: During the process of elimination, i replaced the Air Control Regulator, or IACV, and now the car runs great! The old on seemed to be partially clogged with black soot, and wasnt operating properly. The misfire has stopped, and the rough idle has stopped as well. Runs so much better! Quote Link to comment Share on other sites More sharing options...
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