p0300. cant fix
 

Okay ii have a 2001 chevy blazer . P0300 multiple random misfire code thats pissing. Me off. So I replaced so far plugs. Rotor. Cap coil wires. I got. The. Truck in april did. The plugs they were. All burnt and when I did. Them with the wires the whole drivers bank was all black and burnt and pass. Bank looked normalish. Wear. Now im stuck still mos fire. Somtimes. When I. Get on it. Especially in firat there. Is a. Major hesitation before I gett full powerr . Sometimes I going down the road miid gear it will. Buck. Like. A horses. Some times. For more than one. Gear. Ii. Also. Sometimes get sulfur. Kinda nasty exhaust small which ii was toold. Was. From bad. Cat and. That a bad ccat can. Also. Ccausee these things please help. Orry about messed. Up words. Phone is. Messed up

Did you install AC Delco 41-993 plugs and an AC Delco cap & rotor? Very important with this engine. Aftermarket stuff should not be used.

Have you checked fuel pressure and leakdown? If so, what were the pressures?

Left bank plugs fouled black could very well be a lazy or dead oxygen sensor, (B1S1). It can also cause rotten egg smell in exhaust.

I kept getting the P0300. Then would pop an O2 sensor code. changed 1, then another would pop. So I wound up running 2 different fuel treatments, in 2 separate tanks, then put a tank of 93 fuel in it. After that, not more random misfires.

Nice to hear injector cleaner work. What kind did you use?
Anyone else out there with that stuff. I was always told there's enough "detergent ", what ever the heck that is, in good gas to not need the injector cleaner.

Thanks all for the help yesterday I finally got an o2 and put it in reset pc and I have drove 100 miles prolly 15 to 20 starts and no trouble codes. Got all my gas milage back I think .how many miles are you guys geting to a full tank. Also I have brake and abs lighys on all the time any idea what is going on

I used Marvel Mystery Oil once, then something my Father in Law said was good, but don't know what it was.


I am slowly increasing MPG as this thing is still cleaning out. My last tank was 16.2 MPG. Big change from 12 I got before. Also, around 200-210 is when my Low fuel light comes on, and I still have 2 or 3 gallons in the car.


As for the ABS and Brake light, my wife had that issue, turned out the wires to a sensor was broke. I would just suggest looking around your sensors, and checking your relays and stuff. Are you having any problems stopping?

no problem stopping but the p0300 code is back along with p0171 p0452 p0500 just came up all on the way home the other night . i went 15 to 20 miles round trip and half way through when i started my return trip lots of hesitation. bad hesitation and stuff like that . i had felt slight hesitation since the light came back on a few days before that . so five miles after the bad hesitation started i was the next having trouble going to 45 off a light . on i down shifted nothing again nothing . stopped at the next light , took off same than started hopping real bad coming to next light. Took off and could not get it over 35 kept going turned and got on it hard and with lots of hoping got it to 40 . I turned into my negiborhood and still losing speed exuest geting deeper till finally even in first gear all i would do is stall. FInally after several minst i finally got it up and going in first gear 10 to 15 mph at 3500 to 5500 rpm 2 blocks to my house. called the people im buying it from and They seem to think it is ecu, moudual on distrubator or some other combo of **** does it sound right for me to think this is the cat????????????:icon_wheel:

Thatt is a lot of codes for sure. can you answer dr hook's questions ?

I do believe it was ac delco we checked leakdown and I dont remeber hat it was but my buddy did test he has same truck and mine held the pressure for 15 min than we unhooked it. O2 was dead caused bad cat