Help(newbie)

I know this has been adressed but i can't find it.I have a 1999 2dr 4wd blazer with the 4.3 w motor.about a week ago it started loosing power.it has 80000 well cared for miles.anyway i did a tuneup cap wires plugs filters whole 9yards.problem still there.in the morning won't take off and pops throught intake 2-3 times clears up quick though then if its warmed up and i shut it off than restart with in a few minutes it won't take off again(bogs badly)for about a 1/2 mile.I checked fuel presser at 60psi at idle and it increases to about 65 opon accelerating.no smell of gas but gas milage seems down.the engine though runs smooth and starts right up i have a snapon mt2500 scaner (no codes found)and still cant prove any problem.any one got any ideas here.I would be greatful.

clean the MAF with brake cleaner and a fine toothbrush.

There are two small sensor wires that can get gunked up. BE GENTLE!!!

Also, replace the fuel filter?

Any check engine lights on?

I have cheched and cleaned the maf and changed the fuel filter with the tune up.the engine light isn't on and my scaner(snapon mt2500)can't find any codes.acording to the scaners trobledshooter it says all the senser values are fine.the only mod on the truck is a k&n airfilter.i did notice some black kind of dry oily soot under the butterfly but was told that was normal

K&N oil is murder on the MAF sensor.

Have you just recently reoiled it?

ya but it was when i gave her a tune up.after the problem started.befor that it was in there for about a year.

What Brand of Sparkplugs did you install and what is the gap on em? How's the wires look on it?

Hi i put A.C. plugs i think the platmum plus what chevy recomended gap is(.060),wires,cap and rotor on it along with a fuel filter and cleaned the k&n filter.The truck ran exactly the same after the tune up.the truck has 80000 miles the old plugs looked good like nothing wrong(nice color).this all came on kind of slowly in the last week.it seems to act like the old quadrajets when they screwed up.like its srarven for fuel but it only lasts about a 1/8 mile and starts to run fine.also truck starts right up cold or hot no long cranking but problem seemed worse in really hot weather.

ok may have something here.I decided to check fuel press.again before starting it this morning.i screwed on the gauge there was 5psi i key it up engine off it went up to 65psi but than settled down to 55psi.i started it and it stayed at 55psi.when i snap the throtle it accel is 65 desel is 50 than returns to 55psi.i guess press is soppost to be 60-66psi so how would i tell if the pump or regulater is bad?there don't seem to be alot of posts dealing with the cpfi injection.and i'm old school mechanic(master)i don't know a whole heck of alot about these

Thank i think i fixed it.even though it looks like the fuel press is slightly low it runs seems to be back to normal.I thought i cleaned the maf sensor good with brake cleaner and brush it wasn't good enof.but with the very carful use of a q-tip and brake clean(noncloranated) poof problem gone.Thanks BLAZER LT for the tip on the k&n filter oil i guess it is hard to get off the maf.

Thank i think i fixed it.even though it looks like the fuel press is slightly low it runs seems to be back to normal.I thought i cleaned the maf sensor good with brake cleaner and brush it wasn't good enof.but with the very carful use of a q-tip and brake clean(noncloranated) poof problem gone.Thanks BLAZER LT for the tip on the k&n filter oil i guess it is hard to get off the maf.

Remember to reset your computer.

Turn your key to ON, Pull your two ECM fuses, turn the key off, pull the negative battery cable for an hour.

opps forgot about that, engine light never came on.i did reset the 'puter with the scaner though.Thanks I probably saved 500 bucks I think i'll treat her to a new set of rotors she needs.also just read your post about the front end clunk(hood hinge)i've been looking for that noise for 2 years and sure enof thats it.I also replaced most of the front end to find it.this sites great.