Some of the different body platform, engine, transmission, axle ratio combinations exhibited the problem more than others. When they figured out the problem, they started switching over. The problem with the "W" system is the poppets get varnished up and either won't open, won't close, or stay partially open and leak. I think GM started using the "X" engine in selected platforms in 2001. I know for certain that 2002 M & L body is equipped with the "X" engine. Not exactly sure when S & T body started using it, maybe some one will chime in.

 

I would like to know for future reference. If not may throw the "w" setup back in if the price is right.

 

Use only MAF sensor spray cleaner. Brake cleaner will probably hurt the sensor. CRC makes a good cleaner. You dont actually touch the wire element just shoot it down, let it dry and hook it back up.

 

Finally got around to posting back, but lost 5lbs in 5minutes and about 8-9lbs in a 10-11minute period. That was a no start just gauge hooked up cycled key till pressure built to max which was 58lbs. Dropped to 50lbs

 

58 is a tad low. needed to have been at least 60.

 

60+ I thought was at startup, not cycle. Let me check what startup and running is real fast.

 

Key ON, engine OFF, pump running, is regulated fuel pressure, that's when fuel pressure test readings are taken. GM does not publish any "engine running" fuel pressure specs for this engine as there are far too many variables involved. Manifold vacuum controls the regulator: Zero vacuum, (wide open throttle or engine off) causes regulated fuel pressure to rise to its maximum. High manifold vacuum, (deceleration) causes pressure to drop. When the engine is off and the fuel pump is running, manifold vacuum is at zero: If the system is operating properly, this is the highest pressure the regulator will allow/achieve.

 

Two winters ago, my combined mileage was around 16 and getting worse each week. I happened to notice a brake smell from the drivers side rear and sure enough, that caliper was stuck. Replaced the caliper and mileage jumped up to ~20 combined.

 

I'm not really sure what changed, but i'm currently getting 19mpg combined and 21 or so highway.

..thanks for the help. o_O

 

Hate to open old thread but better than starting new one. I havent drove this thing alot since post maybe few thousand miles. But no brake issues or anything above and still fuel in the intake. I did use a used spider vin-x as I said I would but my leak down is still the same and around 59 or so key on for several minutes and still no codes. Im very stumped at the moment. In fact I think mileage is worse.
I literally got 100 miles to half tank. I did clean my maf. And it must work I did unplug while running and it immediately stalled. I did notice that if I look in the intake after a drive I can smell the fuel and it steams a bit im guessing from the unburnt fuel laying on intake. I will not rule out the spider being used but with the leakdown test being ok is it really possible? Also exhaust temps still hot at the tailpipe.
Should I try cleaning the egr?would that dump raw fuel back in with no codes? I have a code reader but do not have a fancy scanner as im a diesel mechanic and have different programs lol.
Also with the new/used spider injectors being at the end of the nylon tubes wouldnt that leakdown detect leak all the way to the injector tips? And I know these injectors sit in the runner holes but are they supposed to be super tight? Cause my old one just squeezing the tip came out pretty easily. Lots of questions but thats all I can do is ask without being able to do on board diag.