Spark plugs out again with a P0300 code.

[Jose]

Nissan sentra 1.8 with 111,000 miles and new drive belt and water pump.

This happened to me about a month ago where the car would not start. so I checked for fuel and spark. There was fuel but the spark was like a orange color. So I bought new NGK spark plugs and I put them on and magically the car stared. now I am back to weak orange sparks and no start.
Possible cause according to the nissanhelp forum are:
– Faulty spark plug (s)
– Faulty ignition coil (s)
– Clogged or faulty fuel injector (s)
– Intake air leak
– Fuel injectors harness is open or shorted
– Fuel Injectors circuit poor electrical connection
– Ignition coils harness is open or shorted
– Ignition coils circuit poor electrical connection
– Insufficient cylinders compression
– Incorrect fuel pressure

The car idles fine once it starts so I doubt any air leaks. The coils don’t have corrosion. And once I get it to start there no lack of power so fuel pressure should be o.k. But I was thinking if it has anything to do with incorrect timing or with a bad ECM or PCU since I read in another forum that a bad PCU can cause the spark plug to go bad… HELP !!

here is the link about bad pcu:
http://townhall-talk.edmunds.com/direct/view/.f195c11 and it is on post #35.

Topic

[Jose]

Oh no… After removing all of the sparks plugs I took a pick down to the cylinders and they looked wet, specially cylinder no.1. There is a pool in cylinder no.1. so check it out by stick in a long screw driver and when I pulled it out i saw coolant. Looks like is going to be the head gasket. I done a head gasket on a 93 Honda Civic but not on a 05 Nissan Sentra. I am thinking if should do it or take it to my mechanic. And it is my daily driver and I need it back to working condition ASAP.

[college man]

sorry to hear that its a head gasket. 🙁

[Author]

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