I'll do my best to summarize here, I know that this is now the never-ending thread. Believe me, I have spent at least, one hundred hours trying your suggestions and those of the dealers', along with my own. I have also spent over $1800.00 in parts, labor and tools. I am really trying very hard here, so I hope you guys don't feel like I am wasting your time. I sincerely appreciate all of your help and I cannot even begin to tell you how much I have learned in the process. I would love to get this sorted and trust the car enough to come to one of the meets to thank you all in person, (sorry to those down-under, I can't afford to travel that far right now.)
First, the stalling is gone, fixed by the new MAF. So, the issue(s) now are the rough idle (not surging or stumbling, just rough), soggy feeling and sound at lower rpm operation. The issue may still be present at the higher rpms, but it feels and sounds smooth above 4000 rpm with good power. Another trait of the issue is the backfiring. Upon decel, the instant I open the throttle again, it will pop loudly. Still getting poor gas mileage. The car has been reliable for short trips, starting and driving with no stalling or hesitations.
Also, the blow-back from the MAF/snorkel connection has likely been resolved. I found that the Subaru tech forgot to put the o-ring in when he installed the new one. I installed the o-ring and corrected the problem. I will unbolt the airbox lid and re-try to see if I am still getting any blow-back.
Is 19 inches of vacuum correct at 600 rpm?? Or 21 inches at 1500 rpm? Are these too low?
-Mechanical timing and cam keyways= good.
-New coils (6)
-New TPS
-New CTS
-New LH O2 sensor (after it threw that code once)
-New MAF, factory Subaru part
-Vacuum pressures as stated just before = goodish?
-Fuel pressures as stated just before = good
-3 different sets of plugs including the factory set = same running condition
-K&N filter replaced with stock
-Dealer claims 170 psi min compression for all 6 cylinders. (I may check this myself later, seems suspiciously high.)
-New upper manifold gaskets
-Removed manifold and replaced all vacuum lines
-Sprayed propane, carb cleaner and starting fluid around engine bay with no surges in idle rpm.
-Seafoamed intake
-3 STP injector clean treatments
-Tried octane boost, no change
-New EGR vac lines
-Cleaned upper EGR pipe
-New gaskets for TB, IAC, and oil breathers
-New PCV and fuel filter (both autozone parts if it could matter)
-Purge recovery system is bypassed and capped at top of TB after the nipple broke off the solenoid
-Car has ECUtune 1.5, Stebro muffler, resonator delete, perrin crank pulley, 82,000 miles and is a 1995 L-AWD model
-No Codes other than the O2 and purge vapor code, as the solenoid is unplugged.
-Spoke with longassname about ECU who advised to check Fuel pressure for injector leak and to check for head gasket leak. The results from the fuel pressure check and the vacuum pressure needle not fluctuating at all, tell me that theses issues are not present. Yes/No?
Will by-pass aux. air to see if it could be leaking.
Does anyone have an extra stock OBD1 ecu I could try????
Chris, will try removing the O2 sensors and running to see if there is in fact some blockage.
Thanks,
