stumbling idle once warm (1 Viewer)

[miahshodan]

Forgive the long story, but it might help isolate the issue. My family and i went camping a few weeks ago and on the way home the 1997 Land Cruiser 80 series (US 1FZ-fE) started running rough and the check engine light was flashing. I pulled over and pulled the spark plugs to see if I could figure out what was wrong. spark plug tubes were full of oil, so I drained them and was able to get home ok. Assumption was that all of the oil in there was pushing the wires up and causing a bad connection.

This weekend I replaced the valve cover gasket and sparkplug seals and cleared the codes (misfire on cylinder 3) and it runs much better pulls fine and has full power. However once the engine is warm it still idles rough and stumbles at idle and just off idle. Not like it is down a cylinder, smooth under power and the idle miss is not consistent, like every few seconds something misses. I am thinking maybe 02 sensor or ECU issue? The other culprits like plugs, wires, etc. seem like they wouldn't care if it was warm or not. A friend suggested maybe the igniter....but I honestly don't know what that does.

 

[BILT4ME]

Forgive the long story, but it might help isolate the issue. My family and i went camping a few weeks ago and on the way home the car started running rough and the check engine light was flashing. I pulled over and pulled the spark plugs to see if I could figure out what was wrong. spark plug tubes were full of oil, so I drained them and was able to get home ok. Assumption was that all of the oil in there was pushing the wires up and causing a bad connection.

This weekend I replaced the valve cover gasket and sparkplug seals and cleared the codes (misfire on cylinder 3) and it runs much better pulls fine and has full power. However once the engine is warm it still idles rough and stumbles at idle and just off idle. Not like it is down a cylinder, smooth under power and the idle miss is not consistent, like every few seconds something misses. I am thinking maybe 02 sensor or ECU issue? The other culprits like plugs, wires, etc. seem like they wouldn't care if it was warm or not. A friend suggested maybe the igniter....but I honestly don't know what that does.

Make
Model
Year

All of that makes a difference since it's not in your signature line.

1fz-fe rough idle/misfire no CEL - Help

My fzj80 isn't running smoothly, slight misfire, ticking from the front/top of the engine. No CEL (sadly) and it runs okay. When the engine is cold, and I first start it up it runs absolutely amazing, no ticking, not misfire, no shaking. Once it warms up and starts reading the sensors it runs...

forum.ih8mud.com

 

[miahshodan]

Sorry, added that detail. I figured since I was adding to the 80 series forum, that would be assumed, but I guess knowing the year and market still matters

 

[BILT4ME]

Sorry, added that detail. I figured since I was adding to the 80 series forum, that would be assumed, but I guess knowing the year and market still matters

Yes, a 3F-E or a 1FZ-FE, or a 1HD-T all seems to make a difference. There were even more than that. All in the 80 series. Then you throw in Lexus vs Toyota and it's another kettle of fish.

Oh, and now that they're over 25 YO, you can include USDM, JDM, UK, AUS, UAE, and anywhere else someone can find them and bring to the USA and ask questions.

But it's still an 80.

Seems I saw another thread asking this same question in the last few days.

 

[miahshodan]

I should probably also mention that I have a check engine for EGR....but have for years without the stumbling I have now.

 

[miahshodan]

Here is an update, I replaced both Oxygen sensors (both upstream and downstream) and it didn't seem to help at all.
Today I replaced the EGR valve, spark plugs, cap, rotor, and wires and she runs like a top again I suspect it was the plugs, but figured it was all good to do.

 

[White Stripe]

Glad you got it fixed

 

[LongDuck]

The "Parts Cannon" hits the mark! It's rare, but it happens...

 

[Kernal]

Did you also check/replace the large air intake hose, PCV or breather hoses??

 

[miahshodan]

Did you also check/replace the large air intake hose, PCV or breather hoses??

I replaced the PCV/breather tubes when I replaced the valve cover gasket a few weeks ago. I also checked for a vacuum leak at the time and couldn't find one.