AK04SS Posted July 8, 2008 Report Share Posted July 8, 2008 These past few days, I've thrown the P0300 code twice in a row. maybe it was my cheap ass or what, but i was at half tank and filled up with regular, along with two bottles of octane boost. before i filled up, the truck was last filled with 90 octane. the truck ran fine. could that be a cause for the CEL? i also swapped my AEM filter with my extra one, maybe it was over oiled? i dont think it would be the cats, cause i don't really smell the rotten egg smell. i added some octane boost and fuel system cleaner (since i couldnt find sea foam) and filled up with supreme. any other ideas as to what would be causing the random misfire code? Quote Link to comment Share on other sites More sharing options...
AK04SS Posted July 8, 2008 Author Report Share Posted July 8, 2008 so now the light started flashing on me. I passed someone on the highway this morning and it flashed for little bit then went back to a steady light. Is a dealership visit next? Quote Link to comment Share on other sites More sharing options...
Justin Lamanna Posted July 8, 2008 Report Share Posted July 8, 2008 check the spark plug wires and the MAF senosr since you changed filters. if you can do a compression test as well. Quote Link to comment Share on other sites More sharing options...
detjoe Posted July 8, 2008 Report Share Posted July 8, 2008 I had a bad wire give me those codes, the clip that hold the wire to the coil pac was missing. Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted July 8, 2008 Report Share Posted July 8, 2008 I hate to say it, but it could also be a bad cat....a bad cat will cause a P0300 (random misfire) and cause the CEL to flash........ Quote Link to comment Share on other sites More sharing options...
AK04SS Posted July 9, 2008 Author Report Share Posted July 9, 2008 damn, i'm thinking it could be a bad cat too. i changed the plugs and wires this spring. i just cleaned the MAF, so i'm narrowing it down to a bad cat. how much would it cost to get it replaced at the dealership? should i look into getting hi flow cats instead? i should probably cut back on octane boost... Quote Link to comment Share on other sites More sharing options...
Justin Lamanna Posted July 9, 2008 Report Share Posted July 9, 2008 how did you clean the MAF sensor? Quote Link to comment Share on other sites More sharing options...
[email protected] Posted July 10, 2008 Report Share Posted July 10, 2008 I just had the same crap happen to me it was throwin that code and I changed plugs wires and cleaned MAF still anytime I got on it at all the light would flash. Luckily I got a couple of Cats from JOEYSS and that took care of it. I would say replace the cats, that sounds exactly like what was goin on with my truck. Quote Link to comment Share on other sites More sharing options...
AK04SS Posted July 11, 2008 Author Report Share Posted July 11, 2008 i used the MAF sensor spray. yeah, i guess i should look into new cats. would an exhaust shop even touch em? Quote Link to comment Share on other sites More sharing options...
Bluestreak04 Posted July 11, 2008 Report Share Posted July 11, 2008 I messed with that CEL for a couple of days aswell. I would hook it up to a Tech2 and it would show a miss fire on my #7 cylinder. Changed the coil, plugs, and swapped wires around to see if the miss fire would move, but no change. Took out the injector and cleaned it out, and runs like a champ now!! I was getting a headache with this damn code!! But I'm glad I found the problem. All I'm saying is check the injectors aswell. Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted July 11, 2008 Report Share Posted July 11, 2008 i used the MAF sensor spray. yeah, i guess i should look into new cats. would an exhaust shop even touch em? Yes an exhaust shop will work on your cats. BE CAREFUL, a faulty cat can become plugged which obviously will restrict exhaust flow, which in time will destroy your engine. If your SES light starts to flash you are supposed to pull over and shut the vehicle off immediatly. A flashing SES light indicates a condition/problem that can cause severe engine/drivetrain damage. I would get it checked out ASAP if I were in your shoes. I messed with that CEL for a couple of days aswell. I would hook it up to a Tech2 and it would show a miss fire on my #7 cylinder. Changed the coil, plugs, and swapped wires around to see if the miss fire would move, but no change. Took out the injector and cleaned it out, and runs like a champ now!! I was getting a headache with this damn code!! But I'm glad I found the problem. All I'm saying is check the injectors aswell. He is getting a P0300 which is a random misfire meaning multiple cylnders. Checking the injectors is a good idea, but I still think he has a bad cat. Quote Link to comment Share on other sites More sharing options...
AK04SS Posted July 12, 2008 Author Report Share Posted July 12, 2008 thanks for the advice. i'm also thinking its a bad cat. maybe it's a good time for dynatechs or OBX LTs. now i have to decide which chevy dealer to bring it to. I'll keep you guys updated! Quote Link to comment Share on other sites More sharing options...
rojo_143 Posted July 24, 2008 Report Share Posted July 24, 2008 I am having this same problem. My truck is throwing the same codes i know it is not my cats because i have OBX long tubes. would not having a tune to delete this cause it or am i looking at plug wires or maybe a coil pack? i checked the two wires on the driver side that are notorius for melting they look fine to me any ideas. Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted July 24, 2008 Report Share Posted July 24, 2008 I am having this same problem. My truck is throwing the same codes i know it is not my cats because i have OBX long tubes. would not having a tune to delete this cause it or am i looking at plug wires or maybe a coil pack? i checked the two wires on the driver side that are notorius for melting they look fine to me any ideas. If you are driving on the stock tune w/LTs and no cats, then yes you need to have the rear 02s deleted(most likely cause for your codes too).....get a custom tune and wake that truck up! Quote Link to comment Share on other sites More sharing options...
haul@ss Posted July 24, 2008 Report Share Posted July 24, 2008 thanks for the advice. i'm also thinking its a bad cat. maybe it's a good time for dynatechs or OBX LTs. now i have to decide which chevy dealer to bring it to. I'll keep you guys updated! If you're not under warranty stay away from lithia! they'll over charge you like they did me Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.