I have a 1995 toyota T100 3.4L V6 automatic that sat for a while and I got up and running great until about a month ago. Replaced the fuel pump, all of the fuel lines, and the fuel assembly and it was running great. Could get on it and get to 70mph no problem for a few weeks. Went to drive it and hopped on the interstate and accelerate and it just fell right on its face. Couldn't get it past 30mph and it would backfire and choke itself. If you're real light on the throttle it works but you can't accelerate hard enough to be able to get on any main street or highway. I've replaced the MAF (after market), idol air control valve, throttle position sensor, air filter, new ignition coils, new plug wires. The truck had a cat delete already done when we bought it. We fixed some vacuum leaks and it ran like a charm when we drove it for a little while. Next day it started doing it again. We pulled the check engine light codes and it came back with P0170 fuel trim bank 1 with secondary codes of P0300 (random misfire detected), P0301 (cylinder 1 misfire detected), P0302 (cylinder 2 misfire detected), P0306 (cylinder 6 misfire detected), P0120 (throttle/pedal position sensor A circuit), P0325 (knock sensor 1 circuit), and P0330 (knock sensor 2 circuit).

I'm at a complete loss on this. Can somebody help?

 

Can you hook up a fuel pressure gauge then drive it?

 

We don't own one but I could rent one and do it.

 

The parts store probably has one in their tool loan program. PO300 is a general misfire code, while 301,302,etc is pointing at specific cylinders. My guess would be a lean condition. Your vehicle wouldn’t stumble if running rich, but it would nose over if lean.
You didn’t t mention fuel filter, but I assume you replaced that. What brand fuel pump, Denso, or generic?

 

Yes, we've replaced the fuel filter twice to make sure it wasn't clogged. I can't remember the exact fuel pump but I don't believe it was denso.

 

Welp, taking the fuel bolt out and trying to put the banjo bolt adapter in the brass piece stripped all of the threads and broke a piece off in it. So, I'm just getting rid of it.

 

So an update. We got a fuel rail from another truck with the same engine and replaced it. Tested the fuel pressure and it was low. Replaced the fuel pump with an OEM fuel pump. It was running great for about a day. Then started doing something different. It has a slow acceleration and the rpms bounce. It will accelerate but again slowly. We replaced the crankshaft position sensor as well. We have no idea what the hell the problem is now.

 

Would anybody be able to help?