a couple weeks ago I was having fuel pump problems. So I decided the install an electric pump in my engine compartment, with a toggle switch to turn it on and off. Connecting the fuel inlet hose to the electric pump and the outlet fuel line to the original manual fuel pump, which I took the manual arm out of the manual pump and ran the electric pump thru the old pump to the carb. Its been a couple weeks since I did that. suddenly my Toyota started having problems. driving on the freeway it started to seem to be misfiring, and wanting to stall. when I stopped to check it out and restarted the truck, it was bucking at idle, running rich and wanting to stall out. I pulled the spark plug wires off and reattached them. it seemed to work after that. but then it started again. So I decided to start by replacing spark plug wires. it did not help. I also replaced distributer cap, did not help. Then I replaced the ignition coil, it did not help. I then check spark in the plug wires and its conductivity and it checked out good. I then pulled the spark plugs and found that all four where showing server signs of running rich. With black, dry, silt covering the spark plugs from the tip to and onto the treads. the symptoms all point to the egr valve. I was wondering if perhaps the problem may be the electric fuel pump? Hoping for some input before replacing erg and checking for vacuum leaks.
I would either put a new old style fuel pump back in. or install pressure regulator
