2002 4Runner 2wd Limted Idle issues after Warming Up NO CEL

[4Runnermex]

Hello Everyone, need some help trouble shooting this. I have a 2002 4runner I just did an engine swap on. Everything went smooth on install etc..

I always reseal the engine,Spark plugs when I do a swap.

here are my symptoms:

Start up its very smooth like a 3rd gen engine should be, after running for about ten or fifteen mins it goes into a rough idle. Runs great upon start up hauls ass without issue.

Very similar to a misfire, I checked all the plugs and they look good(new), wires are new. Coil Packs doing they're job.

NO CEL!!

Idles low when in gear 5000RPM shakes very much like a misfire during this process

Ive gone thru the simple trouble shooting and cant come up with any other ideas. Plugs, wires, coilpacks

things I haven't done:
cleaned tB


HELP!!

 

[Jhelms]

Generally with the 01-02, this is a TB issue... Well part of your issue is... Happened on both my... 01 and 02. Does your idle bounce at all at random times? Idle appears low which is a sign... The missfire at 5Krpm is not good at all (why in the world are you running it to 5K rpm? - did you mean 500?)

If it is a bounce at all or low idle (idle below 500RPM)...

You must remove the TB to clean it. Open the butterfly and use a small wire brush and carb cleaner and literally scrub the area where the butterfly seats when closed. After scrubbing, the butterfly should be able to rotate backwards a degree or two passed closed. Also there will be a little access panel on top of the TB. It has Phillips screws that hold it on. Remove this and you will see 6 or 8ish small holes. Again, open the butterfly and clean these holes out and any black gunky built up. I use a pick tool to get them clean and back to flowing as normal.

Re-assemble and all should be fixed up!

What happens is: The TB gets dirty and literally cannot breath at idle. This pulls the RPM down to the point the engine starts to stutter. The butterfly closes against the thin layer of gunk that builds up and that tiny amount of needed air will just not flow properly. Once that is cleaned up - your idle will come right up to normal.

 

[cashmoney]

I'd also check for vac leaks.

 

[4Runnermex]

Generally with the 01-02, this is a TB issue... Well part of your issue is... Happened on both my... 01 and 02. Does your idle bounce at all at random times? Idle appears low which is a sign... The missfire at 5Krpm is not good at all (why in the world are you running it to 5K rpm? - did you mean 500?)

If it is a bounce at all or low idle (idle below 500RPM)...

You must remove the TB to clean it. Open the butterfly and use a small wire brush and carb cleaner and literally scrub the area where the butterfly seats when closed. After scrubbing, the butterfly should be able to rotate backwards a degree or two passed closed. Also there will be a little access panel on top of the TB. It has Phillips screws that hold it on. Remove this and you will see 6 or 8ish small holes. Again, open the butterfly and clean these holes out and any black gunky built up. I use a pick tool to get them clean and back to flowing as normal.

Re-assemble and all should be fixed up!

What happens is: The TB gets dirty and literally cannot breath at idle. This pulls the RPM down to the point the engine starts to stutter. The butterfly closes against the thin layer of gunk that builds up and that tiny amount of needed air will just not flow properly. Once that is cleaned up - your idle will come right up to normal.

Thanks I just spoke to a Toyota tech and he's telling me he same thing.

I'm gonna disassemble the throttle body this afternoon and disconnect the battery to get it to reprogram all over again.

Meant 500 rpm

Thanks

 

[4Runnermex]

I'd also check for vac leaks.

I checked for leaks, but if it it's a vac leak it's would do it upon start up most of the time.

Gonna double check and clean the TB

 

[cashmoney]

I've seen vac leaks do weird things. It's worth checking.

 

[Bstrom]

Thanks I just spoke to a Toyota tech and he's telling me he same thing.

I'm gonna disassemble the throttle body this afternoon and disconnect the battery to get it to reprogram all over again.

Meant 500 rpm

Thanks

Clean the MAF as well. You'll have it off when you pull the TB.

You can also pull the ECM fuse for a minute or so to reset it. Might be a duplicate effort to pulling the battery negative cable but think I read it is better than just a battery disconnect. Might be imagining this...

And the PCV valve is worth a look see. That little bugger can cause a lot of grief.

 

[02_SE_Runner_DAD]

keep us posted if the TB cleaning does the trick.

 

[4Runnermex]

keep us posted if the TB cleaning does the trick.

Ok I'm back with an update.

Throttle body didnt fix the issue.

I feel stupid by saying this, I missed the check engine light bulb being out. (NO CEL) really stupid of me.

Ran the scanner and had a cylinder 3 misfire. After I did plugs, cool pack.

Compression test 180+ all six, checked harness good

BAD INJECTOR!! How stupid do I feel now. Runs like a champ!

Bad CEL bulb threw me for a major loop