TCC Shutter or Misfire

dowsewashere · Aug 9, 2017

Hello everyone,

Background on the truck, 1998 Tahoe LT with the 5.7. I put a newer rebuilt 4l60e with a S10 converter (higher stall, aka 40mph in OD is like 1100rpms). I'm getting bucking around 40-50 where the TC would lock and unlock. My issue has to do with when we were finishing the swap my buddy got shocked by coil wire. So I changed that and now whenever I put the truck under light load in low rpm (1000-1300rpms) in overdrive I cant tell if the tahoe is bucking due to the TCC solenoid or the trucks missing. At idle the truck seems to have a mis when I barely rev it up in neutral. But if I was in 3rd gear it does do it or if I get into there isn't an issue. Above 50 I can give partial throttle and it will either down shift or just accelerate (RPMS 1500+)

Truck has a new fuel filter, plugs and wires were done a couple of years ago, fueling system is original at 163k. Are there other tests to figure out which it could be.

someotherguy · Aug 9, 2017

If you're sensing what seems like a miss under a no-load condition then it probably IS a miss. Injector (poppet valve) issues, regulator issues, marginal fuel pressure, etc. though generally you might expect a P0300 out of those. Don't overlook the rest of your ignition system as the Vortec caps are prone to failure and you can't tell by looking at them, the way you would an older cap with visible carbon tracking inside. If your other wires besides the coil are still the couple years old then you'll want to look at them for any damage. Watch it running in the dark for any arcs, for example.

Richard

dowsewashere · Aug 9, 2017

So i went and checked, and whatever hack did my plugs and wires 4 years ago left like half of the plug wires touching each other. SO I'm going to do the spray bottle trick to see if that is one of the issues. I seperated them with zipties roadkill style and it still burbles at idle. I guess some sort of fueling or spark issue? I'm hopeful that it isn't got to do with the transmission because it wasn't hard to put in.

Also is there a possibility there is a grounding issue that could cause that? something maybe grounded to the transmission itself.

big_mike · Aug 10, 2017

I'm chasing a bucking at about that same speed range on my 99 tahoe. I changed, maf, plugs, wires, tps, cap, rotor, cam position sensor. I was getting a misfire code, maf code, O2 sensor code.

It's been down a while now bc of it, my next round of stuff will be trans filter and fluid, all new O2 sensors and thinking about new billet distributor for good measure.

If all that doesn't fix it I'm seriously thinking about pulling the fresh 4L60e and converter out of my 97 Z71.

dowsewashere · Aug 12, 2017

Well NOW my truck is doing it underload around 50+, I am not getting a code for either TCC Solenoid or misfire. I'm going to do the spark plug wire test tonight. I may go out and see if I can read its fuel pressure and see if my pumps on its way out and pull the plugs too. Still runs top but there is a slight hesitation at idle in park and neutral when I rev it so I have a feeling it isnt the transmission.

dowsewashere · Aug 12, 2017

I may also thing my O2 sensors might be the issue as the exhaust came off the truck for several days and we had to drill and punch the studs out of the catted mid pipe section. But idk what to look for aside from the electrical and fuel pressure.

I still know my buddy was shocked by something near the transmission fill and check tube when we were filler the new transmission and we assumed it was the coil wire.

Possible ICM?

dowsewashere · Aug 17, 2017

I finally got around to looking and I notice with the good ole water trick there was a ton of spark leaving the bottom spark plug boot jumping straight to the headshield around the headers. So I will be replacing those and the spark plug themselves to see if it fixes my problem. Its happening at 39-40mphs, 55, and all around in between those mph...

Kmac · Aug 17, 2017

dowsewashere said:
Hello everyone,

Background on the truck, 1998 Tahoe LT with the 5.7. I put a newer rebuilt 4l60e with a S10 converter (higher stall, aka 40mph in OD is like 1100rpms). I'm getting bucking around 40-50 where the TC would lock and unlock. My issue has to do with when we were finishing the swap my buddy got shocked by coil wire. So I changed that and now whenever I put the truck under light load in low rpm (1000-1300rpms) in overdrive I cant tell if the tahoe is bucking due to the TCC solenoid or the trucks missing. At idle the truck seems to have a mis when I barely rev it up in neutral. But if I was in 3rd gear it does do it or if I get into there isn't an issue. Above 50 I can give partial throttle and it will either down shift or just accelerate (RPMS 1500+)

Truck has a new fuel filter, plugs and wires were done a couple of years ago, fueling system is original at 163k. Are there other tests to figure out which it could

Kmac · Aug 17, 2017

Have you checked your fuel pressure?

dowsewashere · Aug 18, 2017

I have not check fuel pressure yet, I can but I feel like this might be an ignition issue because of the spark leaving the boot causing weak spark under light load. I could be super wrong about this. It is just annoying to deal with some days because some some inclines its fine and some its shuttering the whole time. I'd rather it throw a misfire or TCC lockup solenoid code so I can fix it.

TCC Shutter or Misfire

dowsewashere

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someotherguy

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dowsewashere

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big_mike

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dowsewashere

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dowsewashere

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dowsewashere

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Kmac

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Kmac

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dowsewashere

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