Gen 1 Deadspot/Falling on its face under heavy acceleration

[BigGriff023]

Hey guys I did a search on this, and haven’t came up with much. My 21012 screw has 114k on it and I changed the plugs at 90k. When I get on the freeway or accelerate hard, it’s almost a complete flat spot where the truck isn’t wanting to get up and go but the engine sure sounds like it is. Sometime it will suddenly snap out of it and I can feel a sudden acceleration.

I have unplugged the battery for a while in hopes to reset the computer and that didn’t help. I did the plugs as mentioned above, but not the wires. Any other idea what may be causing this or has anyone else experienced this?

 

[Dane]

Ew. Does the engine actually rev up higher, but doesn't put the power down? A video might help, but my first thought is tranny. Do you have a tune?

 

[BigGriff023]

Ew. Does the engine actually rev up higher, but doesn't put the power down? A video might help, but my first thought is tranny. Do you have a tune?

The engine doesn’t rev up higher, it’s almost like I’ve got a heavy trailer holding be back. I only have the Diablo Intune which has been on it for 3 + years.

 

[Dane]

The engine doesn’t rev up higher, it’s almost like I’ve got a heavy trailer holding be back. I only have the Diablo Intune which has been on it for 3 + years.

Is it actually sticking in 6th gear and not downshifting? Wrench in the dash? Odometer or speedometer doing anything weird?

 

[tltoronto]

try unplugging your throttle pedal, and if you have a pedal commander, unplug that and see if it helps.

 

[BigGriff023]

I don’t have a pedal commander or anything like that. No lights or anything electrical at all. It’s usually in 2nd/3rd gear getting on the freeway. It’s simply like I’m towing a heavy load and the truck wants to go, but just can’t. I’ll try unplugging the gas pedal tomorrow as well as the battery for good measure

 

[MTF]

Coils go weak with less miles then you have, it could be with new spark plugs it's more pronounced now.
Also you could have damaged the spark plug wires and or the coil pack connection with the inner spark plus.
If the coil is weak the spark will blow out at compression under load.

Does the Diablo device allow you to see codes and data logging?
A couple of miss fires usually doesn't always throw codes but will log it as pending if it does happen.

 

[EricM]

Brakes sticking and releasing maybe?

 

[Joey Closets]

You could have a bad TPS (Throttle Position Senor)

 

[KTag98]

99.99% likely it’s not this, but don’t forget that the throttle blade isn’t opened fully until after 3500-4000 rpms even with your foot to the floor on these trucks. Could be that after changing the plugs you’re feeling this “dead zone” down low even more now.