Missfire-but leaning toward MAP sensor

[Turbotrux]

Ok.......this problem has been progressivley getting worse. At first I thought CAT was bad - removed it - same problem. Here's where I'm at with it:
New CR42TS (gapped .035)
New Tailor Spiropros (replaced the Red Hots)
New cap & rotor (Conrad)
Replaced IAC motor (had an extra one)
New pickup coil
Ign coil good (Replaced 2 yrs ago w/GM Stock)
O2 sensor was replaced a few years ago - it is transitioning like it should.

At an idle or cruising, it sounds like it has a BAD miss....so that's when I went through the ign system.......this morning I rechecked firing order - OK......unplugged the vac line at the MAP and ran some water through the system to decarb it and of course it through a code but it ran SMOOTH!! very rich, but SMOOTH - I plugged the MAP line back in, cleared codes and - BANG...runs like ass again......my integrator is high at idle - like 157~160 and climbs to 200ish when you give it gas - way too lean. Could my MAP sensor be the problem?

Thanks

 

[bdubb]

didn't the vacuum leak just raise the idle speed?

 

[Turbotrux]

Yes....idle speed went up.....but if I leave everything hooked up - normal - and hold my foot in it at 1000, 1500, 2000....whatever, it pops and farts like it has a miss........w/ the vac line to the MAP unplugged, it idled smooth - no indication of a miss. I was going to yank a few more vac lines in different places and see what happens, but the old lady is dragging me out of here now. :evil:

 

[V6 Kompressor]

when you "yank" the line off the map sensor, you basically tell the ecm that you just lowered the intake vacuum, and need more enrichment... ie. need more fuel.... check vacuum lines, gaskets ect... have datamaster hooked up and record some o2 values, crosscounts, stf, ltf values and I gaurentee you, You will know what the hell is going on inside your engine, you just have to know what to look for... To me, from the info you have wrote... you are runnin lean.... check fuel pressure at Idle and wot or wfo... (wide open throttle or wide fucking open)... and remember this saying from the seventies... Don't Be fuelish...

 

[Turbotrux]

I have done pretty much all of that.......I use Diacom.
O2 sensor is transitioning as normal (crosscounts)
INT is high (lean)
BLM is normal (128)
I'll get out a bottle of propane and check for vac leaks - I've already checked the lines - but who knows....might have one a gasket.

I know I am lean......and the way it runs and sounds if I try to push it past 6psi boost, I'm afraid WOT will really break something.....

When the MAP is unplugged, the INT goes to 80 (rich) and from there, like I said earlier it runs smooth - just stinky rich. I was leaning toward MAP sensor because other items checked out OK - but then again, I don't want to just replace parts until it's right - that's not too smart.

thanks & I'll have another & another & another & another look at it!