brus brother Posted November 13, 2020 Share Posted November 13, 2020 130K miles. been getting intermittent p0303. Sometimes full on crappy running, sometimes just a pending code. swapped 1 and 3 wires and code stayed 0303 assuming coil sprayed water but didn't get a sparkly light show any other possibilities other than coil? If coil any thoughts of Intermotor brand from advance Auto? Quote Link to comment Share on other sites More sharing options...
Numbchux Posted November 13, 2020 Share Posted November 13, 2020 (edited) 4-cylinder, I ASSume? Those are wasted spark, meaning if the coil was bad, it would effect #3 and #4 The FSM diagnostic page for P030x is 5 pages long, checking wiring, power supply, injector, vacuum leak, spark plug, compression, etc. If you know the plugs are good, I'd swap the injectors on that side, and pull the vacuum line off the regulator (vacuum dumps right into the #3 plenum). If it doesn't follow the injector, print out that diagnostic, get your DMM, and start testing. Edited November 13, 2020 by Numbchux 1 Quote Link to comment Share on other sites More sharing options...
brus brother Posted November 13, 2020 Author Share Posted November 13, 2020 forgot to mention it always seems weather related like If the car has been sitting in my damp garage. which is why I started spraying water around looking for arcing. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted November 13, 2020 Share Posted November 13, 2020 any oil in #3's plug tube? Quote Link to comment Share on other sites More sharing options...
brus brother Posted November 13, 2020 Author Share Posted November 13, 2020 1 hour ago, 1 Lucky Texan said: any oil in #3's plug tube? nope had the vc gaskets and plug seals done less than 5 k miles ago when problem first arose. serious leakage back then. checked them again last night and verified they are dry now. Quote Link to comment Share on other sites More sharing options...
Mike104 Posted November 15, 2020 Share Posted November 15, 2020 Stick with an OEM coil (get one from a pull and pay yard if able) and use Subaru or NGK wires only. But definitely do the FSM diagnostic troubleshooting. Could be lots of things if it's not coil, wires or plugs (which you seem to have eliminated all). Quote Link to comment Share on other sites More sharing options...
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