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O2s were unplugged. It's always fun taking over someone else's problem. At least the truck runs decent now & I didn't hit it with the parts cannon. Going to do a full tune up & see how she does....

UPDATE:

I started playing around with it & pulled the plugs. All saturated in gas. Cleaned them & blew out the cylinders. Fired right up. But
It doesn't idle right but runs great under some...

Heres a log file with 2 cranking attempts

No. I didn't want to waste the credits on a bad pcm if that's the issue

Absolutely. I'll get one tomorrow asap

I recently bought it as a crank, no start. So not much history on it. I'm just trying to go thru the process of elimination. Apparently the previous owner put in a new fuel pump thinking that was the...

I did pull power to the pump but didn't clear it out. I'll give that a try tomorrow. I do have another ecm I can try. Are the gen4 like the gen3 where it wil fire for a second then cut off?

This would be a 1st for me as well but I've ran out of ideas. I have 65psi fuel pressure. Spark at every coil. Power at every injector. But I might be wrong but shouldn't it still fire with ether?...

I'm getting no -neg pulse to the injectors. Grounds all look good & have continuity. All injector grounds have continuity at the pinouts. I don't have a security light but I tried the 30 minute reset...

I have a 2010 Sierra that I believe has a bad ecm. I'm reading that a new ecm needs to be programmed to the vin. Can I just get a used ecm & delete vats with my mpvi? Or does it 100% need to be...

Im not experienced enough to know what lazy o2s look like but here is a short log after those o2 settings....

Here is the last tune & log

I would remove the air cleaner then with key on engine off, have someone hold the pedal at different positions and hold. Then verify that the throttle is responding correctly

Is it dbw? Could be the pedal is not matching the tps

Noted. I will post the tune when I get back to my pc

Just recorded another short log. LTFTs to me look spot on for the majority of cells it hit but still looks lean on the WB. Only 1 smaller backfire that time but still stumbling at acceleration. MAF...

During acceleration & occasionally will have a small backfire/puff at idle

When I was working on the MAF tune, I was seeing small knocks on the graph so I took some timing out. 1 or 2? until I saw nothing on the graph

Here is the 3rd log after multiplying by half on the LTFT table. The closer I get to 0, the worse it runs. Stumbling, popping/backfiring, sounds like shit. It also looks to me like its reading leaner...

OK guys, sorry for the long delay but I'm back home from a much needed vacation. SiriusC1024, I loaded the tune you sent & also set the ECT timing advance back to the stock setting. As for mods, this...

I'm out of town for the next week but I'll be sure to give that a try when I get back. I'm still learning how to to read the logs let alone tune so I do appreciate the advice

So if I'm using a wideband, I should be running in open loop?

It's very possible that I tuned it wrong. But if I followed the directions correctly, I did have the ve & maf pretty close

No that was after I had corrected an issue. They do show the issue im dealin with now which what looks to me like it's running very lean at lower rpm.

Wideband gauge does match what shows on the scanner... but I do occasionally see a flicker of "---" on the gauge. So I was thinking it may be a ground or power issue but the scanner afr reading is...