Intermittent engine electrical problem 2012 2nd Gen. Is this a ground issue?

My 2012, 5.7L Tundra is having an on again off again problem with engine management, and I'm wondering if it might come down to grounds.

The general scenario (here in the SW, with regular 100plus temps) is that it drives fine and performs well, but after being parked for a spell (usually in the heat), it stutters and/or stalls when slowing or coming to a stop. Temp sensor shows perfect , right in the middle. Check engine comes on, and strangely 4Lo, and TRAC off. The only way to keep going is to put it in Neutral and keep the rpms up when stopping. Generally at this point it can still run at higher engine speed.

Disconnecting the negative on the battery to clear codes, and having the hood open for a few minutes usually sets things right, and the truck runs normally again.

When codes have been checked while the problem is exhibited, they have been varied, including stalling history, rough idle, low O2 sensor voltage, and low MAF voltage to name a few. But they aren't always the same.

A buddy with a shop researched a little and suspected the fuel pump ctrl module. Replaced it, but the issue returned. In addition, I replaced the MAF sensor when that code showed up. Again, problem not solved.

Has anyone had such an erratic issue and been able to solve it?

I'm beginning to think that system-wide, things aren't getting consistent voltage (ground) when things heat up. Metal expansion plus a bad cable or connection? Alternator? PCM?

Any experience or advice is greatly appreciated!!

 

Plus cheezy stock batt terminals IMHO. Clean all your batt connections, ensure your ground is good, check cables for corrosion.

 

How olde is teh battery? An internal fault/flaw that opens up once hot could be your issue.

 

Can't say. Same battery that was in it two years ago when I purchased the truck. The question has come up once or twice while trying to figure this out, but my response has always been that it's never had trouble starting etc. It would probably be worth it to replace to find out. But if it turns out the battery is the problem, I'll have to kick myself, lol.

 

Have it load tested.

 

Thanks for the feedback! I replaced the battery which was in the truck when I bought it and was about 3 1/2 years old. Even though it never gave trouble on starts, I felt like it was worth it if it was the problem. I also doubled up the main body ground with a 6ga. The factory one was a little bit frayed at the battery end crimp. Opted to throw on the additional cable because I didn't have time to do the full replacement. So far so good, and the truck is performing normally again. Since I did both the battery and the ground, I can't report if one or the other was the cause. When I have time to fool with it more, I can remove the auxiliary body ground to see if it was indeed the battery.