I'm at a loss here just recently got this truck and it's causing me all sorts of trouble. It starts rough and will misfire most of the time on cylinder six (driver side closest to the rear) here is a list of parts I have thrown at it so far. new coil, distributor cap / rotor, plug wires, plugs, fuel pump, fuel filter, coolant temp sensor, TPS sensor and new fuel injector above cylinder six. I've cleaned the throttle body and IAC. truck runs at a real high rpm, around 2500 rpm at 65 mph, it burns black smoke out the exhaust under heavy accel or going up hill. I have done compression test on all cylinders and is approx 120 to 125 psi on all cylinders. Any ideas anyone?

 

also forgot to mention truck has automatic transmission and is not throwing any CEL and yes the light does work also there are not any cats equipped on the truck at this time but yes it still has O2 sensor

 

Did you check the fuel pressure regulator (FPR)?

 

when i tested the pressure it seemed normal I have only tested once I could check if it is changing I thougght if pressure was off it would be flooding all cylinder / starving them?

 

Pull the vacuum line off the fuel pressure dampener and see if it has gas in it.

 

Turns out yeah it was the fuel pressure regulator, still seems strange to me that the fuel pressure had no real change while running, also it was weird the vacuum line did not have fuel in it right away. It took about 45 sec to 1 min of idle and then fuel began squirting out.

Thanks for the ideas and advice running great now.