Some background.... I've been posting in the Tuning with EBL thread, however since this was not an EBL problem (self induced) I thought I would post outside the EBL thread in case someone else runs across this issue.

I confirmed MAP sensor is good by pulling vacuum on the inlet, and referencing the EBL WUD with the key on engine off. Others can do the same with a scanner and compare the voltage output. Also confirmed Fuel regulator by pulling vacuum, and found the adjustable pressure screw leaks a little. This was over several days and countless emails back and forth with RBob, as I initially thought it might be a tune issue.

I had removed and replaced the plenum to add the FP regulator / injectors / FP gage on the fuel rail / and all the o-rings in the fuel rail. When it went back together I started it up, and the engine stumbled badly and was extremely rich, EBL showed Hi-MAP code 33. Which leads me to believe theres a vacuum leak somewhere.

Grab my squirtbottle and soak the intake listening for gurgle as the water sucks in (nothing). So I tried WD-40 around the gaskets (again nothing). Frustrated I moved onto running down wiring issues, then checking MAP/Fuel reg/ ect.

Well I found it! I'm embarrassed to say it was a large upper plenum leak on the underside of the runners where I couldn't hit it with the squirt bottle last time...

So I tried a modified trick I read about online, I taped off the intake and the exhaust with gorilla tape and pushed some cigar smoke in the MAP vacuum line. I noticed some smoke coming from the underside of the upper plenum (and from the throttle body butterfly bushing) but couldn't pinpoint it exactly. Smoke doesn't exactly like to go down, but it will follow the path of least resistance which is why I taped off the throttle body and exhaust.
Then I hooked up my air compressor tank and just cracked the valve a little so i could hear air rushing in, didn't want to blow any seals, so just enough to puff out the gorilla tape on the intake.
Then I hit it with the leak detector (soap/water), I noticed the FP reg had some small bubbles at the threads of the pressure adjustment screw (as we were discussing), and again at the throttle plate bushing (I suspected this a little), but still couldn't find the bigger leak I was hearing. I started feeling around under the plenum and bingo felt the air rushing out at the passenger side top runner gasket.

Now I just have to figure out how I did not get the runner torqued correctly... It may be the gasket I used. I noticed the ones that were in it were press formed to have a seal line around the opening, and the new ones I put in were just flat.

I may put a dab of silicone around the threads on the FP reg pressure adjustment screw, or maybe some thread sealant when I have the plenum back apart next.

I have to say I am quite relieved to find it, thank you RBob VERY much for your support and many emails!!!

 

glad you found the problem ...