Here's the scoop, it's a 1988 toyota sunrader that was sitting for a few years. It's a 1 ton truck with a fiberglass camper and has a 22RE 2.4l, automatic transmission.
When started cold it runs great and starts first turn every time. It will continue to run perfect until it gets a bit warm (10min idling) then it will start to miss in no particular pattern, completely random. Sometimes it will be 10 seconds between misses and sometimes it'll be 2-3 minutes between misses.
It's really random. It only happens at idle, and not noticeable while driving (no hesitation or bucking)
When I come to a red light the idle will start missing at random again. It's more violent feeling when in drive with foot on the brake at a light then in park or neutral, maybe just because it shakes the cab a bit more. One thing I noticed is that the previous owner removed the vsv and I'm not sure if he did the delete properly but I just passed California smog last week and the tech said he noticed the miss and took a look at the report for me. He mention the c02 numbers were a bit high and said it's likely a lean miss fire and advised looking at the fuel system but that wouldn't explain it running great when cold.
I looked for a vacuum leak 15 times to no avail and all the plugs look good and exactly the same as each other.

When I bought it I flushed all the fluids, swapped air, oil and fuel filter, replaced fuel pump and cleaned tank, new plugs, wires, cap and rotor.
Dropped the trans pan and it was clean, changed filter and replaced fluid.

And help would be appreciated, I'd rather not take it to a shop.
Many thanks.

 

Someone mentioned on this forum last week that their fuel pump worked fine when cold but acted up after running a bit. Other things that will make a weak pump work harder is a clogged filter or dirty pickup screen in tank.

 

Thanks for the reply. The pump is new.. I know it could be a faulty part but right now i'm gonna rule that out. The screen is new and the tank was washed and dried by me. The filter is also new. The injectors however, are not new. The tech specifically mentioned injectors but again, with it running great cold it doesn't make any sense to me.
I've gone through 5-6 bottle of techron fuel injector cleaner, 3 oil changes with seafoam and now I'm at a loss for what it could be.

 

Have you tried to narrow it down to a certain cylinder? If you pull the spark plug wires off one at a time while it's running and misfiring, the one that isn't firing will not effect the idle of the truck, the others will make it run even worse when pulled off.

So say you narrow it down to #2 not firing, then you can shut the truck off and swap two plug cables, both on the plugs and distributor side, and see if the misfire follows the wire. If it doesn't, you could swap two spark plugs and see if it follows the plug. I would do that before looking at injectors.

That being said, I've read the factory splices just back from the injectors is a common culprit in intermittent misfires.

 

Electrical and heat are not friends!

Inspect the wire (NE pickup) from the distributor to the ignitor, ignitor to ECU. Any breaches or rockhars rubber compromise the signal. Make sure it's not routed directly over hot things and the heat shield is in place on the exhaust manifold (if you have one).

Another common culprit is the injector wire bundle where it runs between the upper and lower intake, you will find the factory splice here. This area is susceptible to water infiltration and crimp corrosion. You can try some harness manipulation and it might reinforce the need to get eyes on it, but it might still not show up until you get eyes on the splice.

A possible third cause is the distributor shaft having worn down, this can make the NE pickup coil trigger a miss. The NE pickup triggers both injection and ignition on the 22re/RTE.

 

Thanks for the response. Now that you mention it, there was some wires that mice had chewed on, that i just wrapped up in electrical tape. The wire from the igniter to the ecu was one of the wires that got chewed but I cut that section of wire off and replaced it. I will go over everything again to double check. Is replacing a section of wire suffice? or will the entire wire need to be replaced?

I'll have to take a look at the splice too, is it difficult to access?

Thanks a bunch.