Vortec 454 idling problem

[8T7K5]

Will your scanner read the values, or is it simply a code reader? I'm curious on the air flow... should be a Hz and/or g/cm^3 number.

Also that P1345 means your distributor is way off. It doesn't throw a code until +/-20-ish, and the spec is +/-2 (degrees)

I got an OEM MAF from the salvage yard when I needed one.

Funny you mention the distributor. According to the Torque Pro app I'm using it shows it's 21° off. I don't know much about engines but that sounded off to me. I appreciate it.

 

[8T7K5]

Will your scanner read the values, or is it simply a code reader? I'm curious on the air flow... should be a Hz and/or g/cm^3 number.

Also that P1345 means your distributor is way off. It doesn't throw a code until +/-20-ish, and the spec is +/-2 (degrees)

I got an OEM MAF from the salvage yard when I needed one.

My app does show values. I looked at air flow but didn't know what I was looking at. Any idea what the magic number is?

 

[8T7K5]

So there's a few different issues here, let's break this down.
EGR valve delete: the engine is expecting to recycle exhaust air, and you've prevented that. The code is being thrown because there is no longer an EGR. If you're going to delete it, you have to reflash the ECM to factor in the EGR delete.
The mass airflow sensor: your getting a code reading too little air is going into the engine. This would cause a rich condition. Check your air filter and intake system for blockages, if there aren't any, pick up a can of MAF cleaner or pick up a new MAF.
TPS: you may have gotten one that's bad out of the box, or another issue, namely one if the other two I mentioned, is making the ECM think that the TPS is giving inaccurate readings.
You'll be fine, these engines aren't too complex, just make sure you're actually solving a problem before you pull the trigger on a new part. With a project like this you're going to fix one problem just to reveal another until it's fixed. I had the same thing happen with mine, just be thankful it appears to be mechanical and not electrical. If you want to keep this truck I recommend purchasing some diagnostic tools. Fuel, oil, and vacuum pressure kits, a multimeter, etc. $100 in diagnostic tools will save you thousands in parts and hours of time.

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Air filter is new, also the inlet is clear as I had also taken off the throttle body to put on a new gasket and clean it up a bit. This morning I noticed a vacuum line I hadn't seen before that wasn't connected to anything, it's right above where the hoses go into the heater core. There's another vacuum line above it that goes across the intake and it's connected, I just have no idea where this other one goes.

 

[RawbDidIt]

Air filter is new, also the inlet is clear as I had also taken off the throttle body to put on a new gasket and clean it up a bit. This morning I noticed a vacuum line I hadn't seen before that wasn't connected to anything, it's right above where the hoses go into the heater core. There's another vacuum line above it that goes across the intake and it's connected, I just have no idea where this other one goes.

Take a pic of the vacuum line and where it connects, it might just need to be plugged. According to your previous posts, I'd say your biggest problem is that timing.

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[454cid]

My app does show values. I looked at air flow but didn't know what I was looking at. Any idea what the magic number is?

Yes-ish. I'd have to double check, but I think hot idle is like 7 (or 9). I don't recall the Hz at all. Mine was only 2g/cm^3, but the PCM would throw codes, and then ignore it and run decently.

Try unplugging the MAF. Our trucks will run out without it. It goes into speed density mode.

My distributor was not way off like yours. It had been 7 at one time, but I adjusted it as close to 0 as I could.

 

[454cid]

Air filter is new, also the inlet is clear as I had also taken off the throttle body to put on a new gasket and clean it up a bit. This morning I noticed a vacuum line I hadn't seen before that wasn't connected to anything, it's right above where the hoses go into the heater core. There's another vacuum line above it that goes across the intake and it's connected, I just have no idea where this other one goes.

Hot water shut off for the heater core? Not very many GMT-400's got those. It was mainly the SUV's, I think.

 

[8T7K5]

Yes-ish. I'd have to double check, but I think hot idle is like 7 (or 9). I don't recall the Hz at all. Mine was only 2g/cm^3, but the PCM would throw codes, and then ignore it and run decently.

Try unplugging the MAF. Our trucks will run out without it. It goes into speed density mode.

My distributor was not way off like yours. It had been 7 at one time, but I adjusted it as close to 0 as I could.

How the heck do I turn it? Plug wires are all the way up against the upper intake. I'm guessing it doesn't take much counterclockwise rotation to get it to where it needs to be? It's pretty tight as it is.

 

[454cid]

How the heck do I turn it? Plug wires are all the way up against the upper intake. I'm guessing it doesn't take much counterclockwise rotation to get it to where it needs to be? It's pretty tight as it is.

Are you sure which way you need to turn it? Maybe it's the other way, if there's more room there.

 

[8T7K5]

Are you sure which way you need to turn it? Maybe it's the other way, if there's more room there.

Did some reading, it says if it's negative (which mine is) you go counterclockwise, positive go clockwise. How much turning does it take?

 

[454cid]

Did some reading, it says if it's negative (which mine is) you go counterclockwise, positive go clockwise. How much turning does it take?

I don't know. I only had to go 7 degrees. I don't think I turned it much. I wonder if you're a tooth off...or if that's possible. I've never taken my distributor out.