DaveLC2

iTrader: (1)

Well when I was taking my car for a test drive from the dealer I purchased it from the CEL came on. I still bought the car because I loved it. Before I took it in to service I pulled the code myself to see what it was. I originally had a P0304 and they did a reflash. All was well for about 3 days and then the CEL came on again. This time it was a P0300. at this point I put about 2,000 miles on my car so I changed the oil, cleared the code, put in a new set of plugs and threw in a 20 oz bottle of Chevron's Techron fuel additive. The car ran stronger and felt more responsive and the CEL was gone. I noticed that the idle was nice and smooth. After about 400 miles the CEL (you guessed it P0300) came back and you can hear a slight miss ONLY at idle. The car still runs nice and I am still getting 22-23mpg in mixed conditions. What on earth is going on. I've searched this forum for P0300's but I haven't found a solid answer to what causes this condition. My car is all stock and it's a 03 and currently has 19,6XX miles. I want to start modding but not before I get this problem figured out. Adding mods to car with issues usually only makes it harder to fix a problem under the surface. Please help because I have the mod bug! Thanks in advance.

Dave

Soon2BEVO

iTrader: (41)

I have a 2005 EVO and I started getting that same code recently too. Not sure why. Same plugs have been in there since for 3500 miles and they're Iridiums. I told Dynoflash and he said dont worry about - so Im not! But that CEL does bother me!