stay outta the mud :flipoff2:

have you checked out the toyota bible for links to a fsm? tons of great info in there to help diagnosis before you start buying parts.

important things to look at are:

1) are you getting enough air/is all air being metered properly by the ecm? this means no excessive restriction in the intake tubing and no vacuum leaks or cracks in the intake tube. the afm is a long ways from the throttle body.

sounds like you have already verified these to be good, as well as the sensors, so

2) are you getting the proper amount of fuel/are there any fuel restrictions? hook up a pressure gauge and verify that the pump is working properly and able to hold pressure, also visually inspect the lines for kinks or other possible restrictions, i just had a very similiar issue (no power under load) with a 3.0 and the problem ended up being the fuel dampner randomly collapsing and limiting my fuel flow amount, weird shit can happen.

3) there is a very slim chance that the problem is with the spark not advancing, check out the distributor, make sure the timing marks are all lined up properly, gap is proper, teeth on drive gear are good. also, verify spark plug condition.

if you test the 02 sensor, and it is staying on either lean or rich, verify that you dont actually have a lean/rich condition before you replace the sensor

 

i checked the air supply thinking it was the air filter like on my 86 22r truck... ran with new filter and problem still occured, i cracked open the Dizzy and there was no evidence of moisture and all the teeth looked imaculate. A problem i have is stupidly over thinking things.. So i checked the FSM's and what not and they all say ignition is the cause of my problem.. but my timing seems fine at idle, i know i should grab a light but my 22r you could TELL the timing was out even a little with the sound of the idle.

Some other symptoms i don't think i listed... Black smoke under load / revs, When i hold at 1500rpm it pops really bad, I'll check all the lines tomorrow when it stops raining.

Also how do i check the O2 sensor? Is it a simple ohm test or what?

P.S. Spark plugs had sooty black on them ... another reason i think ignition is the problem ..

P.P.S. First EFI vehicle and love mudding :flipoff2:

 

well if you loif you love muddin, then you will learn everything about your truck because mud makes a mess of shit :flipoff2: some people you just

 

cant reach.

sorry about double post, my phone sucks.


black smoke and fouled plugs points to either weak ignition or waayy to much fuel getting in. you can get enough fuel to cause a rich misfire, similiar to a lean misfire, that will cause poor performance.

might be worth checking to fuel pressure and injectors, make sure nothing is leaking. simple and free or under $40 worth of tools if you need to buy a gauge.

as far as ignition, it could also be the coil failing causing weak spark.

if the o2 sensor is reading wrong it could be telling the ecm to dump in more fuel to make the a/f ratio proper, do you have any exhaust leaks at the manifold or flange near the sensor?

inside the diag box there is a port you can connect to with a voltmeter, analog is easier than digital, and you want to see the sensor go from lean to rich (near 0 volts to near 1 volt) roughly 8 times in 10 seconds. or 10 times in 8 seconds, the fsm will say for sure.

the sensor could be stuck at lean or rich and be working properly, so it is important to verify all other potential issues before replacing the sensor

 

had the same issue with my 85 -- adjusted the AFM , was ok for a while and it started up again. Swapped in a different AFM. Havent had any issues since...