Head Install - P0300 Misfire Error
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From: Little Rhody
Head Install - P0300 Misfire Error Just finished installing a set of Dart 205's. Car has a VHP cam which is 216/224 .551/.551 115LSA which is not too radical but is a little lumpy on idle. Had no codes prior to the heads, but now it is throwing the P0300 and when I look at which cylinder, it is all of them not limited to just one. I can't detect a misfire and the car absolutely runs fantastic from cold start to running hard. I have not yet had it tuned from the head installation, is this a normal thing to have happen?
That is a common problem that can be corrected with tuning. The P300 misfire code is being triggered because of the rough idle caused by the cam. the PCM is looking at relatioship between the cam and crank sensor and see's an irregular pattern. Either turning off the the p300 code or raising the values in the Misfire Low rpm at idle parameter will stop it. The latter is the better option as you still should have misfire protection at higher rpms.
Thread Starter
TECH Senior Member
iTrader: (4)
Joined: Jul 2004
Posts: 8,092
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From: Little Rhody
Probably should have explained better, cam was already in the car this was a cam only change. However, compression ratio should be higher with these heads.
