Quote:
Originally Posted by cthomsen99
Sorry to hijack this thread but I'm having similar issues. Recently purchased 1999 Limited with 271K miles. Started having rough idling and got codes P0300, P0304, and P0305. With unknown prior maintaince, I put in new denso plugs and wires and did a seafoam spray treatment. Runs great when cold but has issues upon warm restart. Compression test shows 170-180psi in all cylinders. Would new injectors be the next logical step? Thank you for any suggestions.
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Misfire codes are either a fuel, air or spark issue. You've handled the spark maintenance items. The other issue could be air that isn't metered correctly. Try cleaning off the MAF with loads of MAF cleaner/carb cleaner and see if that helps the stumble and misfire. Also change your air filter 1x per year.
The last would be fuel delivery which is controlled by the front O2 sensor and our friend once again, the MAF sensor. It could also be the injectors but if you haven't ordered them already, put 1-2 bottles of high quality injector cleaner such as Lucas, Royal Purple, AMSOIL. Avoid bargain brand stuff. If there's any improvement, even slight improvement, it may be the injectors causing the misfire. Instead of replacing them, send them off to an injector cleaning service as it'll only cost about $125 for the service + shipping. You might even find a local place like I did and have no shipping costs.
