99 yukon acting funny

[vaughnd]

i have a 1999 gmc yukon 5.7 litre v8 4wd with 108,000 miles on it. it has been running like a champ until just recently. with no engine light on, i noticed that the idle was running low while in park, and then it sputters a few times, as i put it in drive and press the gas at a normal take off, the engine sputters and shuts off. ive recently cleaned the MAF, replaced the air filter, no new fuel filter yet, but the spark plugs and wires are, and the fuel pump seems to be working. until now there have been no problems. i rechecked everything to make sure there were no vacuum problems and there werent, the air intake is fine and the throttle body is clean and in good shape, also it starts up fine, and no black smoke leaves the exhaust, but water seems to be dripping out. Now, as i give it gas directly from the throttle body, it revs perfect with no problems, but when i go inside the truck and actually hit the gas pedal to rev the engine, it sputters and stalls, and it wont rev past 2000 rpms even with the pedal all the way down, and it also back fires with a popping noise out of the air filter box, i also notice that the crank fuse has no power going to it, could this be the problem? or does the problem seem more like a fuel filter or fuel pressure problem? im confuzed and am not sure what too look at, at this point. please help!

[intrcptrbird]

Crank position sesnsor possibly? Although I dont know why it would rev when done by hand. Not sure whatelse to say.

[vaughnd]

see i thought the same thing, why would it rev different, for some reason it does tho. i havent checked the crank position sensor, but now that its said ill check it. the engine will gradually let me get up to speed, but if i mash the gas, it almost shuts down completly, so im thinking its a sensor somewhere if not the crank position sensor. thanks for the help and will get back soon to reply with what it may be!

[2000CAYukon]

What did you clean the MAF with? The wires are very sensitive and you should use a cleaner safe for electionics. Did you add a K&N or similar filter?

Also check the fuel pressure, should be 60-65 psi at idle.

//2000CAYukon

[vaughnd]

i cleaned the maf with an maf cleaner that was labeled on the can, so that was safe, i also checked the maf wires and they were not corroded, rusty, dirty, etc. i have an aem dryair oil-free air filter, and that helped the performance before the problem. i havent check the fuel pressure yet and will do. i noticed that the distributor cap and rotor pins to the wires were corroded with a build up on them. could there be too hot of a spark from the plugs (platnium 2's) ruining the cap and rotor, and contribute to this problem? thanks for your help and info!

[intrcptrbird]

Dont think the wear of the cap and rotor are caused by anything other than it might be an old cap and rotor, or a cheap cap and rotor, or it got some water in there. Change those. Even if thats not the problem a good, new, clean, cap and rotor cant hurt. And dont cheap out and buy crapy ones or else you'll just do the same thing in about 3 months.

[Yukonite]

If it revs fine with manual throttle-body movement, then have a look at the accel pedal postion sensor. It sends info to the Ignition Control Module wich controls ignition spark, idle control and such.