89 TBI 350 stumbling around cruise

[jim_in_dorris]

I hear you. I am not backfiring through the intake, but the exhaust. This seems to me that it is caused by excess fuel in the exhaust , which gets hot and occasionally explodes.

While trying to find replacement heads, I looked at a lot of 193 heads. Out of the 8 I looked at 7 were cracked. A burned exhaust valve is common on these heads. Have you done a compression test.

[89S10_Project]

Well, I apparently had replaced the grounds in the past, with 10GA to each head, to a stud on the passenger fenderwell used as a ground terminal (yes, very hack, I agree, but all I had at the time). I added 2GA grounds to each head, just forward of the intake. ran them to a buss bar, found here: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Ran a jumper from the battery to the buss bar as well. Ran another from the firewall under the coil bolt, to the driver's side (also where all the sensors get their ground).

Added a red version of the above, to the driver's side firewall. Ran all my aux circuits to it, and it's fed by a piece of 2GA. Replaced the alternator wire (factory, approx 10GA) with a piece of 2GA. All terminals are hammer-crimped and soldered, with marine heatshrink over them.

It's too soon to tell, but she sure seemed to run better this morning. I doubt this was all of the problem, but it may have been some.

I also note a new development on my gauges. The oil pressure gauge used to read fine on cold start, then go to nothing on hot idle. I'd verifed with a mechanical gauge that it was fine so I wasn't too excited. Now, with key on and not running, it shows pegged at 60PSI. running, same thing. Drops to nil at key off (as it should). I think it's time to pull the panel and check my grounds on it. I likely have some issues there, at the very least I need to replace bulbs. That may well be part of the issue, actually- absent groundplane due to the bulbs being blown. I have LEDs to replace them, just haven't had time to suss it out.

My neighbor has a 97 Tacoma he wants to sell, for $2000. The truck books out somewhere around 4G. Done! 22MPG with cold air, and a parts runner (bed) so I can get some of the unwiledly crap I've been needing to get (engine for the jeep) as well as household stuff I need to run to the dump taken care of. It's a no-brainer.