Spray some WD-40 inside your rotor cap... replace the o- rings and put some dielectric grease on the mating surfaces...
I've found the 2nd leading culprit for backfire and bucking is MOISTURE

 

Are we talking backfire out the exhaust or up into the intake. Intake would suggest a bent or burnt valve or ignition problem.

check all the usual stuff like cap and wires and a compression check wouldn’t hurt too

 

ive got brand new cap rotor and distributor but I’ll spray some WD-40 in there today when I put it all together. I finally got my knock sensor so im putting it back together today and crossing my fingers that that’s the issue

 

I had the windows down when it was doing it and it definitely sounded like it was coming from the back.

 

The distributer bolt that locks it down is in an elongated slot. Where does that bolt sit in the slot? kinda in the middle, or is it pretty far to one side? Same with the TPS. Middle? or off to the side?
I did look at a schematic supplied by Autozone for the 1994 4Runner. It does show the wiring from the ecu to the MIL light is VIO(I assume violet) so that cut wire could very well be the one to the dash light. You can ohms check it, or just go ahead and solder it back together.

 

yep distributor is about half way and the tps seems to be a little off to one side.

 

So at idle take a fresh dollar bill and hold out over the end of the tailpipe with one hand on the end ... let the dollar bill work like a flapper and see if sometimes it sucks the dollar bill into the exhaust instead of just bouncing it off end... if it sucking you have a valve problem.
have you set your valves?

 

Any progress? Find a problem and fix it?

 

I replaced timing belt and knock sensor. Ran great for about 5 mins then started acting up and doing the same ˟˟˟˟ again. I can’t put anymore money into this thing. I’m gonna have to sell it for parts or wait until I can take it to a mechanic.

 

I tried the dollar bill trick and it wasn’t sucking at all.
I haven’t had my valves set.

 

Were you able to fix the "Check Engine" light?

I would want to make sure that the light works correctly first. It might give you some clues as to what your problem is.

 

Was wondering if MIL was now working, too.
Curious, anything else been removed or bypassed besides the cat and A/C system?
Does it look like someone reglued(silicone) the cover on the air flow meter?
Just trying to guess where someone might have messed with things.

 

I connected the cut violet wire back to where it is was and I was unable to get the light to come on with a confirmed working bulb. That is the worst problem to have. Do you guys know if I could hook up and diagnostic reader to the obd1 port and still get a reading if the CEL isn’t working?

 

Just to cross it off the list, I'd do a continuity test on the VIO wire from the connector at the ecu to the bulb socket.

One thought I pondered was a missing or bad ground. Randomly checking probably would be difficult, but if someone here has the Factory EWD manual for that year, or even one close, it'll have the ground point for each component.
For example: in my 1987 22RE, the EWD manual shows the ground point for the ECU is the ground connection at the intake manifold.

 

Okay I’ll look for one and check that out. I’m starting to think it’s a fuel pressure issue. Runs just fine at idle and through 1st gear but when you hit second it’s starts boggin then spins back up for a second and then goes into bucking. Then when you left off it goes back to normal until you get back on the gas. And it feels like I have a dead pedal.

 

Could be. You could probably borrow a fuel pressure tester from a parts store tool loan program.
But I'd really get the ECU MIL up and running first.

 

sounds good will do! Thank you man!

 

i am not familiar with how the '90-95 trucks/4runners handle the MIL/CEL.

for an '87, if the CEL circuit is inoperable when the key is initially turned to "start", the engine will not start. it will crank, but it will not run via combustion until the CEL is working. i had an intermittent non-op CEL for about 5 years on my #1 '87 4runner, but cycling the key would always eventually get the CEL to illuminate, and the engine would then start. i believe during this intermittent issue, when the CEL wasn't lit while attempting to start, that the fuel pump wasn't running, and that jumpering the B+ and Fp ports wouldn't make the pump run, either - until the CEL would illuminate. once the CEL came on, the truck would fire instantly and run just fine. the cause of the issue was a corroded EFI relay. once replaced with a known good relay from my '88 parts rig (with a 3.slow - same part number for both engines), the CEL issue has dissappeared. the relay was heavily corroded, and transferred the problem to my other '87 4runner (#2), when i popped it into that one to check.

my point is that even if the CEL isn't lit, the ECU portion might still be working, just bad wiring between it and the ECU, because you can get your truck to start without that MIL/CEL being "on" during key start; '90-onward might not be the same.

 

This probably won't help, but I had a similar problem with my 93 22re p/u. And no CEL then either. I went through quite a few things, focusing on the fuel system before I started looking harder at the ECU. If I remember right, the 93 ECU was different than the previous years and was more expensive. My neighbor also had a 93 and let me swap computers with him to help diagnose the problem and then I found a used replacement. Don't give up on it. Remember to KISS

 

Would it help if I uploaded a video of what it does? Like take it for a drive and show y’all?