3.4L stuttering under load

hey all! I am in the middle of my cross country drive as I move from dc to Marin county CA! I am currently in Moab and I first noticed this problem in Kansas. Currently I have a 2002 tacoma 3.4 4x4 manual. I do have a motorcycle in the back and probably carrying quite a bit of weight (750lbs +). When I am going up hills the truck will stutter. It got so bad going up to the mountains from Denver I had to pull over; I was having trouble going over 40mph. I just happened to have bought spark plugs a few weeks ago and they were sitting in my truck. I pulled over, swapped all 6 plugs and I was on my way, no issues. I was then going from summit county CO to Salt Lake City UT and going through those canyons I began to stutter again. I pulled over and I also happened to have bought wires the same time I bought plugs so I swapped out the wires. I noticed 2 of the wires were pretty corroded so I felt assured this would solve my problem. No issues, we made it to salt lake fine. Then I began to stutter coming out of salt lake going up into the mountains towards Moab. I then pulled over (I had bought steel wool to thoroughly clean the connectors in the coils in the case it stutters again) and used steel wool to clean the metal on the coils as best as I could. I made it to Moab no problem. Today I got to do a little off roading and while the truck was not under load began to stutter. I am not waning to replace the coils unless I know that is the problem ( I hope it is the coils because that seems the easiest to fix). I have read some people saying to clean the tps and maf, however, I don’t have the tools to check and clean these systems. Does anyone have any insite? It typically will only stutter after hours on the road with a ton of weight in the bed at high rpms. Any advice would be amazing. Thank you so much in advance.

-Jake

 

Sounds like you may have bought a bad tank of gas, try running it till the gas light comes on and fill up with chevron. This worked for me, found the vette guys do this to stop it. Could still be spark though, how old are the coils? Mileage?

 

Check engine light come on at all? Do you have a code reader or anything capable of reading fuel trims?

 

Its ether a coil or an injector

 

https://www.tacomaworld.com/threads/bad-coil-pack-questions-from-a-old-timer-here.607313/

 

I don’t know anything for sure however I have gone through multiple tanks of gas so I think I can elminate that.

No check engine at all, I have a cheap code reader that won’t be able to help more then showing a pending code.

Is there a way to test injectors? I also was wondering if it is a good or bad idea to put in injector cleaner stuff or is that stuff no good?

 

The truck as 115k miles on it, just did spark plugs and wires, I am thinking of replacing the boots too while I’m at it as those could easily be bad since the spark plugs and wires we corroded.

 

It's an injector if there is no code.
Click the link to the thread I posted.
I'm not gonna post all that again.

 

I just read through this and it helped a ton!! Thank you so much for posting it.

 

My question would be though, why would the problem be instantly fixed (for a day or so with lots of driving) when I mess with the plugs, wires, and coils if it’s the injectors? Maybe a combination of everything?

 

Theres a short in the injector or its sticking.
Mine tested fine when cold, had to wait till it was hot and shuddering and test it while it was hot to find what one ohm bad.

 

thinking about this for while and you are going to need a scan tool to help in diagnosing this. I agree that starting with the secondary ignition is a good place to start but... the fact that is hasnt illuminated the CEL does not mean that there isnt a code, it is just "pending". Pending meaning that the parameters to set the CEL havent been met yet, so many misfires etc.

Multiple things here to explain.

If and when you get a code reader and you see the misfire code P0300 that means multiple cylinders misfire. That is something is effecting ALL cylinders as opposed to a P030X where X is the affected cylinder. The P0300 is either fuel or air because that it the one thing common to all 6 cylinders. The 3.4 uses a wasted spark ignition where each time the coil fires it fires once for the cylinder that is at TDC compression and once for the cylinder that is on TDC exhaust so if you get a 2 cylinder misfire code see if those cylinders use the same coil, if so, the coil is suspect.

For the P0300 I would first suspect the fuel filter, then the pump, then the injectors. Each of these is testable but not on the side of the road.

I have driven that SLC to Vegas to San Diego and there isnt much there except long streches of pararie and desert.