The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support Kiggly Racing
Please Support STM Tuned

Bad Misfire bad o2 sensor?

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

98mitsubishigst

10+ Year Contributor
1,526
16
Nov 17, 2008
Pittsburgh, Pennsylvania
So every year after driving 200+ miles to the shootout, i seem to come driving home and 25 minutes into the trip my car at cruise decides to misfire terribly to the point where it'll eventually die and i have to pull over. Heres what happens;

I would be driving along and this misfire would come around 3000 rpms and when you tried to give the car more gas it would bog and would choke itself. I couldn't even WOT. I noticed every time this issue came around and i pulled over to shut my car off, after 10 seconds I could start the car up and the misfire would be gone for 10-15 minutes. So i switched my stock gauge to run as a front o2, and i would notice after the 10-15 minutes, the gauge would drop to the bottom and stop moving unless i let go of gas. So i did some logs and i would notice when the car was running fine in cruise my voltage would go from 20-70 and back and forth, but when the issue came the front o2 voltage would read .04 and 0. Could this be the issue?

So to get home, id haveta turn the car off and wait ten seconds and turn the car back on and the car would run right. What is everyones opinions?

Posted is a log i took, if you look at the very end of the log you will see the o2 dies off... (Sorry my wideband wasn't logging but at the end of the log you can see where the o2 stops and thats where the misfire is.)
 

Attachments

  • o2.elg
    139.8 KB · Views: 59
I didn't open the log yet but I would guess it's not the o2 sensor reading bad, but more so something is going. Wrong and the o2 sensor reports what's going on. Possible ecu issue. Injector etc.
 
Car will rich but driveable without an 02 sensor.
Please check Spark and Fuel components. When weird shit happens it is usually bad grounds.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top