Help needed - Random miss ( Lugging ) No codes

[NC4runner83]

I'll list out the symptoms and the actions I've taken thus far.

2005 4Runner Sport - 223K
Both Head gaskets replaced around 140K ( due to the known defect ) other than that no other major repairs or issues till now

On a Saturday morning about a month ago I had very rough idle / miss fires, my plugs were over due for replacements. I replaced those with the Pre gaped NGKs for the most part that fixed the rough idle / misses. Here's where it gets interesting.

Initially in the mornings when I warm my car up or start out driving everything is fine, typically about 3 - 5 miles into driving I have what I would call lugging at around 1500 rpms, and when I come to a stop. I can put the car into neutral and this seems to help with the lugging ( seems to increase the RPMs a tad ) When I'm driving over 2000 rpms either the lugging goes away or I'm going fast enough where I dont notice it. I didnt receive any codes initially, so while doing some research I decided to try a few things.

*No loss of coolant so I don't believe its a head gasket issue again.

1) Sea foam cleaner ( poured into full tank of gas ) no change.
2) Cleaned the MAF sensor No change
3) pulled the throttle body off, cleaned etc. No change
4) Spaced out the Bank 2 Sensor 2 ( which I did receive a code during the symptoms P0430 ).

So I'm sort of at a loss.... My next thought was pulling the injectors out and cleaning ( which at 230K they probably need ). What puzzles me is that I'm not receiving a mis fire code while the lugging is happening so I cant isolate if this is on a cylinder or a particular injector?

Any thoughts, Ideas, others that have had the problem that can provide fixes would be appreciated.

Thank you,
James

 

[bpchura]

James,
I've had a similar problems with other trucks but never with my Toyota. What it ended up being (after new plugs, which helped) was the coils. Our trucks are coil on plug which means one or more could be bad. I would test then with a multimeter and see if any fall out of spec on primary or secondary winding. If all are in spec, I would see if any are different from each other and try switching those out. I've had coils which have had resistance within spec but still cause problems when they get warm or in extreme cold. Best of luck and I hope you find your issue!

 

[NC4runner83]

Thats a good tip. I'll try that. I thought about buying a new coil pack and rotating it around to see if I could isolate.

*I've had one coil pack go bad in the past and it didnt act like the current symptoms. Regardless if I were at a stop light or driving down the highway it missed badly, pretty much unable to drive*

Also if it were a coil pack wouldn't it throw a code?

 

[bpchura]

I would imagine it would throw a code but when I had it happen in the past (again not a Toyota) it would take some time and many misfires to register a code. Might be something to look at! My mind is set on ignition for lugging problems so if plugs are good I go to the next level up! Good luck, these small running problems are a pain in the butt to deal with and leave you with a lot of headaches!

 

[Rodtheviking]

Does it smooth out when the RPM's come up? If so, I would say injector seals or clogged/worn injector.

 

[NC4runner83]

It seems to.... I cant say for sure, but it feels like it does. Anytime I'm over 2K RPMS its seems to run smooth, or when I'm accelerating over 2K. When I'm at stop it lugs some (randomly), not a heavy, but its there or.... when I'm driving and the rpms drop below 2k, and I slightly press the gas its there.... why it was leading me to believe it was with the fuel... whether it was plugs (which I have replaced), or injectors.

* I can shift into neutral / park at stops and it seems to help, this increases the RPMs.

Thoughts??

Thanks,
James