I do have a MAF coming tomorrow. It was $70 new from a company called Walker via Amazon. I just did a fuel pressure test and not running the fuel rail was at 30-31psi and then running it droped down to around 22-23... That seems low to me. I know the rave says it should be 33-36 but the drop at rev seems like a lot to me. Is there a value for what the drop should be when running? I replaced my fuel filter a week ago so that shouldn't be the problem.

 

The fuel regulator functions by vacuum. Lower rail pressure while running to me means more fuel was being sent back to the tank. You might be onto to something though with the misfire codes in that they are a symptom of the regulator being faulty. Regulators are not known to have high failure rates in general but since you have a high mileage vintage vehicle it could be a factor. You can check the fuel regulator vacuum diaphragm with a vacuum tool to make sure it's not perforated/leaking.

Copied from the Rave;
Fuel pressure regulator
The fuel pressure regulator is located at the rear of
the engine in the fuel rail. It consists of a fuel inlet,
outlet, vacuum port and internal diaphragm.

When the engine is under high manifold depression,
the applied vacuum sucks the diaphragm off its seat,
allowing fuel to return to the tank, resulting in a lower
fuel pressure. This is necessary because the high
depression will try to suck the fuel from the injector,
resulting in overfuelling if the pressure remained
constant.

Failure will result in a rich mixture at idle but
normal at full load, or a rich mixture resulting in engine
flooding, or a weak mixture. Although the fault will not
illuminate the MIL, faults caused by the failure may be
indicated.

 

I will check out the fuel regulator but I don't think that's the problem because my CEL always comes on when I am at 1200-1800 RPM and going slow (15-30Mmph) like a up a hill or in town. What the RAVE describes is it running rich at idle with regulator problem because the regulator doesn't open and causes high fuel pressure at the injector. Then at higher RPM it works out cause there is a need for that higher pressure. I guess if my cylinders are beeing flooded at idle it could be the extra gas running through the system causing the fault. I'll go throw some dried chicken bones in a jade bowl and let you know what comes out.

 

Dried chicken bones in a jade bowl works for me, I've tried working your problem out in secret and so far draw a blank.

 

It cracks me up how many people have these codes pop up after a rebuild/overhaul of some sort and how there isn't hardly an mention of a solution or solid cause.

 

That's because even though the guts are refreshed the sensors are same ones prior to the new shiny surfaces..... What sensors where working and what weren't prior to the rebuild is a crap shoot from out here, really. The flashing CEL is signaling pending doom, the cats are melting, the cats are melting......

What readings are you getting from the O2's? Uppers should match each other pretty closely as would the lowers with each other. While I'm on the subject..... how old are the O2's?

 

The O2 sensors are matching their voltages in bank 1 and 2 sensor 1 and 2. Those values are constant with variations I would expect. The voltages stay around 0.9-1 volt with the rears reading 99%. That is using live data and recorded live data that was recorded when the fault presents. The O2 sensors are old but I am not going to replace them until they are a problem. I see all the time people saying to replace them just cause they are old. I will not do that because I don't have the money and it doesn't appear to be the problem. I just put in the new MAF and the CEL has not come back on after 15 miles. The vacuum and barometric pressure values have changed quite a bit with the new MAF installed. I will report after driving to work a couple of days on whether the CEL turns back on. It seems to be running a little better with the new MAF too, it has a little crisper throttle response but again I will report back in 2 days.

 

Fingers crossed for you.

Regarding the fuel pressure... yes, yours is low as you noted. How old is the fuel pump?

 

Probably same age as the O2s......

 

The fuel pump was never replaced since I had it in the past 1.5 years. So ihscouts is probably right. My CEL turned back on again this morning about 200 yards from my driveway, I am going to get the O2 sensors and other live data and post that here. I am waiting for the motor to cool so I can trip the fault again as it is more likely when it is cold. I may be chasing a valley pan gasket issue after all. The valley pan gasket does clunk like an oil can at times so maybe I just need to bite the bullet and get to taking it off again. It could be the low fuel pressure too because the LTFT were at -14.2 so now its trying to lean itself out since the adaptive reset. I reset the adaptive values again after seeing that thinking that maybe the new MAF needed an adaptive values reset to work right. In torque when I installed the new MAF the vacuum and barometric pressure readings changed. The barometric pressure made more sense with the new MAF at 12.7(I am at 2500 above sea level and it was a hot day) and was showing 14.7 with the old MAF. So I was thinking that the old one was throwing wild numbers and the ECU was defaulting to sea level (sea level or one bar being 14.696 psi. My diving/submarine days coming back to me) or something like that. When I hook up a vacuum gauge to my manifold it is reading 16in/hg to 20 in/hg with vacuum increasing with RPM.
Summary
1: Got new MAF installed it on cool motor (about 90 deg outside) drove for 15 miles no CEL
2: Monday morning head to work on cool motor (62 deg outside) and CEL blinking about 200 yards from driveway the same place it always does.
3: Called into work cause I'm a douche, hooked up innova with live data. Notice the LTFT and STFT are both negative the LT being -12 and ST being -6
4: I clear adaptive values again and verify with the Innova that the values are reset. They are, both LT and ST trims are at 0.0 when I start again.
5: Think to myself if there has ever been a change in how the engine runs or if better throttle response is all in my head.
6: Set the Innova to record live data 50 frames before and 50 frames after the activation of a DTC, the CEL never turns on for 15 miles. Come back home and park it.
7: Check the vacuum in the block (with engine warm) to make sure its not a ring issue (compression test was good as stated before) that was 2 in/hg or around that.
8: Checked the vacuum at the manifold were the PCV valve is and it read 16-20in/hg depending on RPM from idle to 1800ish RPM.
9: Wrote this list realizing I spell vacuum wrong every time.
10: Waiting for motor to cool so I can start this whole cycle all over again.

Again when the motor cools I will get those O2 sensor values and all other live data so you guys and gals can see what I've been seeing. But I want to trip the codes again, if they will (I crack me up) so you can see the whole picture.