I'm hoping someone can help me with my rough-running 4Runner. It only has 65K miles but has been idling poorly for the past 6 months. It's almost like it is missing and seems to run worse on humid days. I've replaced the plugs, plug wires, O2 sensor, fuel filter, air filter and have even done the Sea Foam shock treatment through a vacuum line. It is still running poorly. Does anyone have any ideas? I'm beginning to wonder if I have a bad fuel injector(s).

Please help!

 

Just so you know, it is a V6 automatic.

Thanks in advance for your help!

 

No codes? Try and have some pulled anyway...they might be stored. At Autozone it's free.

Also, what kind of plugs were in it, and what kind did you go to?

 

I don't believe there are any codes, but I haven't checked. I figured it would throw a CEL if it was throwing codes.

As far as plugs go, I pulled stock plugs out and put stock (Denso) back in.

 

I'm wondering if it could be a coil pack(s) or fuel injector(s). Anyone seen issues with these?

 

I know it sounds too easy but when was the last time you cleaned the throttle body?

 

were these symptoms that you experienced before you did all these things?

 

I did have these symptoms before I did the major tune-up, and I did clean the throttle body and MAF sensor.

 

based on what you wrote:

- you have not changed out your pcv. read midiwall's most recent thread on changing that out

- if you did the seafoam last, you've probably fouled up your plugs and 02 sensors. that is why most people (or those people willing to read through pages and pages of threads) either swap in some dirty plugs and 02s, or do the seafoam at a time/mileage interval where they will change the plugs/02s right after the seafoam

bob

 

I'm sorry I didn't mention it earlier, but I have changed the PCV valve. Also, I did the Seafoam treatment with the old plugs and O2 sensor in place because I didn't want to risk 'coating' the new plugs and sensor.

To be clear, here is the order of work performed to date:

1. Seafoam treatment
2. Checked all vacuum lines for leaks
3. Replaced PCV valve
4. MAF sensor cleaning
5. Throttle-body cleaning
6. Replaced Air filter
7. Replaced spark plugs and wires
8. Replaced fuel filter
9. Replaced O2 sensor

 

So no one has any insight for me? I thought someone in this group would have seen this type of behavior. Anyone?

 

My 96 has been acting up as of late also. It kinda acts like it's flooding or something. I'll be curious what you find. Keep us up to date.

 

Wish I could be of help...Keep us updated though, and we'll all know next time.

 

Shot in the dark here, but have you made sure that no "new" air is getting into the system post "sniffer" (MAFS) by checking the intake tube and all its silencers, etc.? Another possibility is an exhaust leak, but generally speaking you get a loss of power with that.

 

Have you tried to reset the EFI or ECU. I read on the other day that when you clean your MAF its a good idea to Unplug the fuses to the EFI and the one that controls your MAF. Might be worth a try.

Tommy

 

Mine did that and it was the #3 coil pack. I had done everything that you did and that was the problem.

 

The only time mine idles really rough at idle is if I have a vacuum leak. Check all your connections from the intake tube.

FWIW, the most common vacuum leak I experience is the small hose that attaches to the back of the power steering pump.