my car had started running so bad that it wouldnt even crank and then when it did it would backfire n stuff n go dead. so i was off this past weekend and pulled the plugs and all 8 were black n wet with gas im assuming so i changed plugs and readjusted my valves cause i wasnt sure about them either. when i first fired up the car ran great!! revs were good n clean with no stumbling. i shut it off and changed the oil n filter and took it out for a test run and by the time i made it about a 1/4 mile(normal driving) it started stumbling and breaking up bad again. it wouldnt even stall up it was missing so bad. so i limped back to the house and parked it. now it wont even idle good anymore. can someone please help me fix this this has been going on for too long. i tried the delteq ignition and it still had the stumble. my left o2 readings were really low(like 200-300 and sometimes around 70-100) the right was a lil better but still not good. sorry for the long post but just trynna put in any info that may be helpful in getting this straight.

 

oh yeah and one more thing...when i hold the throttle to about 3k rpm the fuel pressure drops down to about 30 psi. is it supposed to do that or ???

 

Fuel pressure should rise slightly when you speed up the engine. Vacuum levels will drop and the regulator should then increase pressure. Check the FPR diaphragm to be sure it doesn't have a hole in it by applying vacuum manually to the vacuum port of the regulator. I like to use a mity vac brake bleeder to do it. You can (if you're brave) suck on the hose going to it.

Based on what I believe you are saying about the O2 readings however, this is not your running problem. To explain further, if the diaphragm were the cause of the both the low fuel pressure AND the rich running condition, the O2s should be seeing a rich condition. But you said they are hovering low, (around 200) if I understand correctly.

Obviously if you have fuel coming out of the vacuum port of the FPR, it needs to be replaced first.

It appears that you have a problem where the O2s are seeing (or reporting to the PCM) that you are always running lean. The PCM then tries to richen the AF ratio.

Based on my experience with burned O2 wiring, you should test the wiring for the O2s to be sure they are intact.

The first easiest test of the wiring is to unplug the O2s and see what the PCM shows for a reading. They should be at around 450 disconnected. If they are lower, you have a short of the 2 signals wires to ground.

So first check the diaphragm in the FPR for leaks then test the O2 wiring.

 

ok thanks ill get right on that thanks a million. as far as i could tell there was no fuel coming out of the regulator vac port so ill check the other things you said. i was wandering if maybe the long tubes had burned some wires or something