Strange power/throttle response :454 burb

[honkon]

Was it shuddering in the 27mph screenshot? Maybe TC shudder can occur with very minimal slip. Not exactly sure. It's shuddering, as if you're driving over rumble strips, while in park?
My mountaineer doesn't idle rough. The TC issues are only present at speed.

 

[Mildphil]

Was it shuddering in the 27mph screenshot? Maybe TC shudder can occur with very minimal slip. Not exactly sure. It's shuddering, as if you're driving over rumble strips, while in park?
My mountaineer doesn't idle rough. The TC issues are only present at speed.

No, at 27mph it had just shifted. And yeah it idles rough after it had shuddered, and only then. Any other time when the truck behaves, it idles/parks just fine. I jad just flushed my fluid earlier, it was a light brown/ and I put 3 gallons of ATF until it came out cherry red. I'm doing the filter and cleaning the pan tomorrow, I'll post updates to see of this has any effect. I'm not sure of it will, but I needed a fluid changed anyway.

 

[Schurkey]

I jad just flushed my fluid earlier, it was a light brown/ and I put 3 gallons of ATF until it came out cherry red. I'm doing the filter and cleaning the pan tomorrow,

That's exactly backwards. Wasteful of ATF, and inefficient at getting the "dreck" out of the transmission. You've already "polluted" your clean ATF by putting it in a dirty pan, mixing it with dirty ATF, and you're sucking it through a dirty filter. Now when you drop the dirty pan...are you going to throw away 5 quarts of semi-dirty fluid, or are you going to save 3 or 4 of those quarts?

Proper procedure would be to drop, inspect, and clean the pan. Change the filter. Install the cleaned pan. Add 5-ish quarts of fluid. Remove the tube at the trans cooler outlet. Install temporary tube at trans cooler outlet, leading to a drain pan.

Start engine, add fluid to trans while old contaminated fluid squirts into drain pan. When fluid leaving the cooler is "cherry red", shut off engine, re-connect cooler tube, and top-off trans fluid as needed. Have a beer.

At this point, you've already spent the time and money, so there's nothing left but to slap a filter on the thing after cleaning the pan. You'll know better next time, though.

 

[Mildphil]

That's exactly backwards. Wasteful of ATF, and inefficient at getting the "dreck" out of the transmission. You've already "polluted" your clean ATF by putting it in a dirty pan, mixing it with dirty ATF, and you're sucking it through a dirty filter. Now when you drop the dirty pan...are you going to throw away 5 quarts of semi-dirty fluid, or are you going to save 3 or 4 of those quarts?

Proper procedure would be to drop, inspect, and clean the pan. Change the filter. Install the cleaned pan. Add 5-ish quarts of fluid. Remove the tube at the trans cooler outlet. Install temporary tube at trans cooler outlet, leading to a drain pan.

Start engine, add fluid to trans while old contaminated fluid squirts into drain pan. When fluid leaving the cooler is "cherry red", shut off engine, re-connect cooler tube, and top-off trans fluid as needed. Have a beer.

At this point, you've already spent the time and money, so there's nothing left but to slap a filter on the thing after cleaning the pan. You'll know better next time, though.

My procedure was almost the same except I just purged the dirty fluid out first. Once I got all the initial fluid out, I then filled the empty pan with fluid until it came out clean. I definitely used more fluid than I needed in hindsight. But either way, the fluid and filter are in now, so I'll have to play with the truck some more this weekend.

 

[Mildphil]

So I drove my truck around for a good 30 mins today. Shifted really nice and fast after that fluid change. No shuddering until towards the end of the drive. About 55 mph on the way back and it was acting up again. At 5his point it was about 95 degrees outside with the engine at about 194degrees and the transmission at 175 degrees. So it seems like it happens after the truck heats up and has been running a while. That's also why it usually doesn't happen until I'm on the highway or towards the end of a drive. I'm at a complete loss here.

 

[Mildphil]

Update: so after changing the cap, rotor, and coil out, my issue seems to have been remedied. I've driven about 100 miles and it's been running great.

 

[Mildphil]

Update:
Been about a month since everything was replaced. No issues at all and my mpg has gone up from around 12.5 to 15, pretty good from a big block. Really happy with it. I'm going to install some Bosch iridium spark plugs soon.

 

[Hartwell]

Update:
Been about a month since everything was replaced. No issues at all and my mpg has gone up from around 12.5 to 15, pretty good from a big block. Really happy with it. I'm going to install some Bosch iridium spark plugs soon.

Did you use delco cap and rotor? I’ve been having similar issues and I suspect my injectors because I’ve already replaced cap, rotor, coil, wires, plugs with no resolve. However, I used Bluestreak all the way through minus wires and plugs.


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[Mildphil]

Did you use delco cap and rotor? I’ve been having similar issues and I suspect my injectors because I’ve already replaced cap, rotor, coil, wires, plugs with no resolve. However, I used Bluestreak all the way through minus wires and plugs.


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No, I used some other brand, but as long as it's quality I wouldn't see why it won't work. Do you have any check engine lights? Could be a bad distributor among other things.

 

[PlayingWithTBI]

No, I used some other brand, but as long as it's quality I wouldn't see why it won't work

I put in a brand new Spectra Premium distributor, another member put in a new PerTronix and the ICMs in both of them failed shortly after. Mine within 3000 miles. I replaced it with an AC Delco and it runs fine now.