3rd gen 4runner misfire 2 & 5

[craist]

So I now this topic has been covered a lot. I have spent many hours researching and testing. I could use some more advice.

1998 3.4 4runner LTD 222,000 kms automatic 4x4

I get pending and faults, check engine light comes on. P0300, P0302, & P0305. Misfire in cylinders 2 & 5. These codes happen all the time and have for 3 weeks. Once and only once did I get a pending misfire in cylinder 1. The truck is running extremely lean. An average reading would be 14.7-1, mine is at 28.38-1. I get no other codes. The codes come on at idle and under load.

Replaced with OEM Toyota parts
Spark plugs
Wires
Coil Packs
Injector #2 (had bad resistance)
Engine Coolant Temp Sensor (had bad resistance)
Alternator
Batteries
All Ground and Positive wires
Air filter
Fuel filter
Timing Belt (20,000 kms ago)
Waterpump (20,000 kms ago)
I have had recent and regular maintenance done following the Toyota schedule.

Tested and is okay
Mass Air Flow Sensor
Injectors
Intake Leak
Vacuum Leak
Vacuum Lines
Coil packs swapped around
Crankshaft Timing Pulley Bolt
Injector cleaner through a full tank of gas
Cleaned MAF
When it misfires, I can barely feel it. The truck runs pretty good now, it shifts better and is much more responsive. Under load I can feel a very little lack of power. It is still throwing the same codes. It constantly does it. Anyone else have some advice?

 

[craist]

Compression Test

1 - 170
2 - 155
3 - 160
4 - 155
5 - 160
6 - 165

 

[40Habits]

Try moving your coil pack off number 5 and see if the problem follows the pack. If it does, your coil pack is bad.

 

[SteveH]

I'm surprised you're not getting a lean code, but I might have a shop do a smoke test and look for harder-to-find vacuum leaks. (I'm not sure how you you tested for vacuum leaks already).

How about testing fuel pressure at the rail (or wherever tested on 4Runners). Lack of power can be due to inadequate fuel.

 

[craist]

Try moving your coil pack off number 5 and see if the problem follows the pack. If it does, your coil pack is bad.

View attachment 678814

thanks for the advice, but read the post. I did that already

 

[craist]

I'm surprised you're not getting a lean code, but I might have a shop do a smoke test and look for harder-to-find vacuum leaks. (I'm not sure how you you tested for vacuum leaks already).

How about testing fuel pressure at the rail (or wherever tested on 4Runners). Lack of power can be due to inadequate fuel.

I had Toyota check the emissions to determine it was running lean. Also had them check for Vacuum leaks.

I also sprayed engine start around the engine to look for leaks myself. I also inspected every vacuum line.

 

[40Habits]

This really sounds like a needle in a haystack. Burn the 4Runner

 

[craist]

This really sounds like a needle in a haystack. Burn the 4Runner

ya I am getting close to doing so

 

[T4R2014]

Have you changed the oxygen sensors? They go bad at around 100,000 miles.

 

[raydouble]

Some other things to check. Since it's 5 and 2, I want to guess it's coil pack wiring related though.

Shorted/rubbed wires to the 5 - 2 coil pack
fuel pressure
Pcv valve
Valve clearance
Power and ground for the ECM