1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

O2 problems/ misfire

Discussion in 'Chevy Trucks' started by 515CUSTOMS, Jan 21, 2010.

  1. 515CUSTOMS

    515CUSTOMS Junior Member
    Messages: 28

    can a bad O2 make my truck misfire?

    Thanks Joe/515CUSTOMS
     
  2. quigleysiding

    quigleysiding PlowSite.com Addict
    Messages: 1,098

    Yes My dodge ran like crap when it needed one.I thought it was the fuel pump untill we ran a scan on it.
     
  3. 515CUSTOMS

    515CUSTOMS Junior Member
    Messages: 28

    the check engine light came back on today i got some new gas and it went off but still runs ruff some time
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Depends on the year, model and engine of the truck. More details would be helpful.
     
  5. 515CUSTOMS

    515CUSTOMS Junior Member
    Messages: 28

    96 1500 4x4 with the 5.7
    with 260,000 miles
     
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Being that specific engine and model year I wouldn't suspect the O2's are causing misfires unless they've been in there for an extremely long time with that amount of miles.

    Did you retrieve any and all DTC codes yet? Have you done any repairs to resolve so far?
     
  7. 515CUSTOMS

    515CUSTOMS Junior Member
    Messages: 28

    it started 3 weeks ago when the check engine light came on. went and had it checked and the code was Random/multiple cylinder misfire detected but the truck ran fine. had the code cleared and over the next week the light would come on and go off before I could check it twice. the next time it came on i went straight to my friends shop to look at it and the same code Random/multiple cylinder misfire detected truck still ran fine. The light stayed off for a week or so. Then the truck started to miss under load with 1/2 a tank of gas and got worse as the tank went down to a 1/4 tank so I put in some heat and some gas up to 3/4 of a tank. the miss got better but didn't go away. Went to have the codes looked up and this time it was the same Random/multiple cylinder misfire detected and 02 sensor heater circuit malfunction ( bank 1 sensor 2). had it cleared and started asking around about the o2 making my truck misfire. did plugs and wires that night because i don't think they had been in some time and trying to find the misfire.it went away for a little bit but the light came back on after 30 min driving around and the misfire came back and got worse when i get down to 1/2 a tank. Right now it just dose it under load and its not that bad.... Ive been working on the tuck since fall with power steering pump then power steering lines. Then the re-man power steering pump went bad so back in to do a another pump. Just trying to get it fixed up till summer. When i can drive one of my other trucks and have some time to work on this one.
     
  8. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Suspected you were getting a random/multiple misfire code. Wouldn't be surprised if it was a fuel issue, either a bad batch or low pressure. Installing a fuel pressure gauge to check for proper FP would be the next step.
     
  9. 515CUSTOMS

    515CUSTOMS Junior Member
    Messages: 28

    60 psi when you turn the key to on 55/52 when its running it. the light came back to day and the misfire got bad at 1/2 a tank. I filled it to 3/4 of a tank and it got better had the code checked and it was the P0300 Random/multiple cylinder misfire detected again.
    and no 02 code
     
  10. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Including while under load?
     
  11. Racer593

    Racer593 Member
    Messages: 71

    B&B, what about that crossfire dist cap? Mine would go from running ok to crappy to not even running a few years ago, depending on the moisture. Changed the cap and rotor and the problems disappeared. Pretty cheap fix too.

    Chris
     
  12. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Absolutely and they are the Achilles Heel of the Vortecs but I always verify proper FP first in a case such as this as it doesn't cost a thing except for a few minutes of time. Once good FP is verified then move on to ignition related items that may be overdue for replacement.
     
  13. 515CUSTOMS

    515CUSTOMS Junior Member
    Messages: 28

    I just went for a drive with the fuel pressure gauge hooked up and its 60psi most if the time. The truck didn't misfire to day. and after reading Racer593 post i started thinking about the last few days and it was raining and foggy and nice today and the first day this started was the day after the car wash to wash the engine bay down after the power steering pump hose went bad. Time for a new cap and rotor.
     
  14. Racer593

    Racer593 Member
    Messages: 71

    Sounds like the same thing that happened to mine. Hope thats it. Quick and easy, well, easier than a fuel pump!!

    Chris