Here's an update, I've replaced spark plugs along with ignition coil. It's actually running worse. It won't rev over 1,500k and dies anytime I come close to it. I've check fuel pressure (60 psi) and that's not the issue. It's electronic timing so there's no adjustment there and the distributor is brand new. I double checked it's installation just to cover my bases. It has a K&N CAI and MAS is brand new. I'm at the end of my rope here. I'm almost ready to swallow my pride and just take it in somewhere. Anything you guys can add would be greatly appreciated.

 

Couple of questions which have helped pinpoint this kind of problems in the past:

• Is it the correct and original engine for your truck?
• Has somebody tampered with the engine wiring - any other part of the wiring (engine bay or ECU related)?
• Have you crosschecked the distributors setting with a timing light?
• MAF connections and wiring (Out of range is too generic a fault code. It will be caused by several things which can be related to wiring, air flow, some conditions with signal vs. engine state as the ECU sees it, and - yes a short in the wiring can have that effect also.)
• MAF installation with the CAI, how has the routing been altered?
• MAF modifications? (Cut out the grid, removed baffles from the duct?)
• Have the faults been recorded "and" erased before the next step in analyzing the problem?

Just a couple of thoughts as we see a lot of these: "It was running more or less but at least could drive it and after changing plugs, coil etc. it's running worse than before."
As 93S10TahoeLT said, many of these have been traced back to incorrect wiring and bad connections, dead batteries and such.

A picture of your setup may help as well. Hope this helps getting closer to the problem.

 

1. It's the original engine with 130k.4.3 v6

2. As far as I know, the wiring is sound. The guy who I got the truck from wasn't really a "hand's on" kind of a guys.

3. I haven't confirmed the timing with a light. I understand you can take a reading from the top of the engine and also the bottom. However, the truck ran fine for weeks, just one day, it started to lose power.

4, The MAF is brand new and the connections seem sound. I only replaced it because a new one came with the CAI.

5.Installation of the CAI was pretty routine. The truck already had one installed when I got it but the manifold had a giant crack in it. I replaced it with the newer one that came with a new MAF.

6.The MAF is stock, I've made zero modifications. The only think that I've done was empty out the CAT and reinstalled it.

7. All trouble codes have been erased after each reading.


Over all, the truck was running fine and just one day, it started having power issues. I took it to a friend who has an advance OBD2 diagnostic computer who told me that it was saying too much air. I refuse to believe that a CAI could do that. I'm going to reinstall the old MAF and see if that has any effect. I've even checked to make sure that I didn't put it in backwards or something stupid. LOL. I've attached some pictures for reference. Thank you for all of your help.



Coil



Coil



Front





Over view



MAF



The MAF is brand new but I'll give it a try either way. Thank you for your help.



You know what, that's actually not a bad idea, I'm going to give that a try this weekend. Thank you for all of your help.



K&N, it seemed universal and came highly recommended. Thanks for the response.

 

Also make sure all the CAI connections after the MAF sensor, particularly the head. Mine came loose one time and acted the same as you are describing.

 

I'm not really into the 2nd gen but most MAF equipped will run with the MAF disconnected.

Then it will depend into what mode the ECU defaults to. If it is going speed-density and the culprit is the MAF then you should see a difference.
If it defaults to limp-home - no good for troubleshooting.

Can somebody of the 2nd gen gurus confirm?

 

You say the MAF is brand new, but what brand is it? I've seen numerous accounts of these trucks not liking off-brand air flow meters and only running right with original equipment. Sometimes a 20 year old used OEM one from a junk yard works better than a brand new one off the shelf from a parts store that was made in China last year when it comes to these.


It'll run with it disconnected, it'll just go into open loop mode, get terrible gas mileage, hesitate and stutter on acceleration, and throw another code at the check engine light (open circuit).

 

The MAF's have very specific calibrations. If the signal is off - your fuel delivery will be off.

The usual GIGO principle in computer systems. (Or any system for that.)

They are very sensitive and blazen_red_4x4 is right in pointing that out. Can cause all kinds of problems. If the MAF also has the IAT (intake air temp) sensor integrated another source of problems. These computers really need these two sensors do deliver proper information as most of the fuel is based on that input.

 

Or "The Hat." I went through that for months. Until I finally saw the light...

.... aaaand....

OP, Do you have a massive vacuum leak at the part of your CAI that replaced "The Hat" ? Mine was so bad I ended up putting the stock one back on, after becoming unwilling to buy the FULL kit (with the stand-off bolts) that cost a few hundred dollars. Just put the old one back on and it runs very very well, maybe a K&N will run better, okay, but I am not spending $400 on a brand new kit to find out...

It barely runs at all without that thing on TIGHT! Can make or break whole engine. Really one zcrew and proper fitting piece. How yours look..... ?