Intake issues... please help?

Guys... i have an 04 silverado... for the past 4 months or so... my check engine light has been coming on and off... every 2 weeks or so and stay on for a day and then shut off... but this week it came on and its now about 6 days that it has stayed on... i took it 2 autozone to do the check engine light check... the machine said exactly:1)vacuum hose off, cracked or passage blocked - Engine mechanical timing condition2) throttle body intake tube loose, off, or cracked3) BARO(barometer)/ MAP ( Manifold absolute pressure) defective4) VAF (vane Air flow) MAF (Mass air flow) sensor dirty or defective

Its a K&N series 77 custom intake... i took it all apart yesterday... inspected the hoses and the intake tube and looked at the mass air flow sensor... nothing seemed to be wrong... although the sensor may be hard to tell... i put it all back together and back on... so i know its not 1 or 2... but then i started my truck and light was still on... so i turned it off... this morning i get in and its off... drive off park it for about 5 hours... get back in, started driving and its back on?? any ideas on what it could be? or how i can check the mass air flow sensor or map sensor better to see if either is defective? thanx a lot guys... any help is appreciated

my truck does that also do you have a system connected if so maybe a wire touched or check the fuse under the hood look in the book that came with your truck and find where it says instrument cluster and change the fuse maybe that could help because the same problem happends to mine another thing you could do since the engine light is on take it to autozone they will check it for free only if the engine light is on dont hurt to try

thanx man... any other suggestions guys?

come on guys... someone has 2 have some idea as to what is happening? thanx

Edited: 9/28/2007 10:09:32 AM by Cruz Lo

You did not post the Code so I cannot be sure, But the description sounds like the MAP is reading an unusual value. This can be caused by a vaccum leak.

Your K&N is the air intake and has nothing to do with the intake manifold. The MAP measures intake manifold vaccum. everything after the TB.

Since it is not always present it could be a defective MAP sensor. But I never would just change something without being sure.

You could check all the hoses that attach to the intake manifold for a potential leak. Like those from the valve covers, brake booster etc.

Also Did you do anything at all to the truck before this problem started? If look there first.

Good luck

i still havent had a chance to inspect this problem but i hope to this weekend? does anyone know how to, if i even can, check the mass air flow sensor and map sensor to see if they are good or not? any suggestions are appreciated guys... thanx

As some of you know as of late, my truck has been nothing but problems and this is an old one that is still continuing... I just put in a new water pump this past weekend and had to take the entire Intake off, so i went ahead and checked the tubes and the MASS air flow sensor and it appears to be fine. I'm leaning toward it being the MAP sensor, but i dont really know. Any more suggestions guys? The troubleshooting code is still the exact same as on my orignal post and the troubleshooting code is P0101. Dont know if that helps or not? thanx guys

THIS IS STRAIT FROM GM
#PI01624A: Service VME - 4.8 5.3 6.0 LM4 LM7 LR4 LQ4 LQ9 GEN III Engines with MAF Sensor Code P0101 - kw driveability fluctuation idle intermittent MAP rough stall surge hesitation - (Apr 5, 2004)


Subject: Service VME - 4.8 5.3 6.0 LM4 LM7 LR4 LQ4 LQ9 GEN III Engines with MAF Sensor Code P0101


Models: .




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When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

SERVICE VME
This message applies to all 1999 through 2004 Chevrolet, GMC, Olds, Buick and Cadillac pick-ups and utilities that are equipped with either the 4.8 liter, 5.3 liter or 6.0 liter Gen 3 V-8 engines. Recent warranty analysis indicates that both the MAF, or mass airflow sensor, and the MAP, or manifold absolute pressure sensor, are being replaced for a MAF sensor code P0101. The cause may actually be a MAP sensor failure causing the MAF sensor code. One of the MAP sensor

Edited: 3/14/2008 4:08:40 PM by 3yrididit

ALSO THE PLASTIC INTAKES HAVE BEEN KNOWN TO LEAK...AT THE HEAD...THIS WILL ALSO CAUSE A MAP SENSOR TO READ INCORRECTLY...YOU CAN CHECK IT BY RUNNING THE ENGINE AND SPRAYING CARB CLEANER AROUND THE BASE OF THE INTAKE IF THE IDLE CHANGES THAN IT ISLEAKING....THEY ARE EASY TO REPLACE..ALSO YOU HAVE A K&N AIR FILTER IF YOU OIL THEM TOO MUCH THEY CAN ALSO CAUSE THE MAS AIR FLOW SENSOR TO FOUL OUT..

wow that was a real quick response. thanks man. So bsaically, if im reading it right, it is saying that i need to check the MAP sensor before anything else? Do you by chance knwo how i could check it to see if it is working properly? I really appreciate it man