:screwy: Hi i've got the jimmy with the 4.3L vortec cpi and it's got a strange problem. it's a littl sluggis accelerating and gets wors the warmer it gets. when i got it there was gas in the oil-changed oil. tested cyl. pressure -all between 90 and 140 psi. good fire- new pluggs, wires, egr valv, cpi injector, cold start sensor and temp sensor. exaust reeks of unburnt fuel. reset the computer then drove a while and not reading any codes. somebody please help!

This sounds like a CPI/regulator/fuel line leak. Very common. Do a search on here and you you find TONS of info on this. You need to pull the upper intake off, and take a look, if you see washing, you have found you problem. Also if your finding gas in the oil(another indication of a leaky injector/regualtor/lines) don't drive it like this for too long, or you will damage your engine.

Here is a great link

http://www.automotiveforums.com/vbulletin/showthread.php?t=473110

Yip, replace the CPI injector and the nut kit.

DO NOT KEEP ON DRIVING IT LIKE THIS, YOU ARE DESTROYING THE ENGINE.

okay but r u saying the steel lines going into the plenum or the plastic ones may leak over time. - just replaced the o-rings and clip that holds the too lines on the cpi unit when i replaced it.

The plastic ones inside the intake, that connect to and from the CPI injector. They do leak over time, especailly if they are old and have been pulled and pushed, like when you had to replace the injector. Easyest way to check for leaks under the plenum, is to take the upper plenum off, get someone to turn the key (BUT NOT START) turn the key to the "on" position, while you watch for leaks at the injector. Again if you see washing, its a tell tale sign of a leak. Good Luck.

okay but r u saying the steel lines going into the plenum or the plastic ones may leak over time. - just replaced the o-rings and clip that holds the too lines on the cpi unit when i replaced it.

You always replace the nutkit when you replace the CPI injector.

the plastic lines r fine no leaks. and there is no washing at all. ???

For now they won't be, but they will eventually leak.

Does it have a mass airflow sensor, or does it use a MAP sensor?

just a map sensr

but the map senser circuit tested out okay along with the sensor so....

Everything inside the plenum is supposed to be greasy-grungy-yuk.
Any clean areas indicate fuel leakage.
Clean areas on the drivers side is the fuel line leakage.
Clean areas on the passenger side is the fuel regulator mounted on the CPI.
You might check your fuel pressure too.

More info & Rliths most cool pics here:
http://www.automotiveforums.com/vbulletin/showthread.php?t=518850

It is very grimy that's the head scratcher. There is no clean area s inside the plemun

Sounds like my '92 with a new regulator & fairly new lines.
Mine 'jes barely makes the fuel pressure spec...about 51psi.
I got my fuel pressure check kit at the local auto parts store...about the same price as having a shop check it.
Here's a pic of where you check it.

http://i131.photobucket.com/albums/p288/Clunk_/Image033.jpg