Since I got my problems resolved with the computer codes I decided to take the stang to inspection today. My usual trick is to back off the timing and fuel pressure since it seems to help keep the emissions down. I set my base timing (spout out) to 4 deg. BTDC and dropped the fuel pressure to 35 (vac. hose off) and headed on over to inspection. It passed rather easily and my NOx & HC numbers were fairly low. I started driving back home and I was feeling pretty happy that I got a new inspection sticker when all of a sudden as I'm pulling away from a light the motor starts behaving like its got a dead miss. It was suddenly running like a dog and my wires & plugs are almost brand new so I'm saying to myself WTF is it now? Anyway, I get back home and hook up the code scanner (the check engine light never came on, but I figured I'd connect the scanner anyway) and the KOEO test throws a 543 (fuel pump circuit - open connection) which had me a little baffled because if the circuit was open the car shouldn't run at all I wouldn't think. The KOER test came back with a 111 so I just decided to reset the computer and set my base timing and fuel pressure back to my usual numbers. I started the car up and took another drive and now it feels fine. Could the low fuel pressure have caused the EEC to misbehave?

 

Huh, thats pretty wierd. The relay could of been kicking the pump off and on or the pump could just be going. I probably wouldn't take long trips for a couple of days just to make sure you don't get stranded.

 

wtf

 

 

I've got a '94GT and apparently the fuel pumprelay is incorporated into the CCRM. I'm just speculating, but I probably have a flaky relay or my pump is on its last legs. Its not that old though. Its a Walbro. I think its rated for 155lph. Any chance the ignition switch could have an effect? Sometimes I have trouble either removing or inserting the key. The whole thing seems to be getting pretty sloppy.