GM 4l80e trans vibration in O/D when towing

[rognelson777]

Going to put new plugs wires and cap on. Injectors were checked last year by a fellow drag racer and they were okay. will check regulator.

Thanks for info. I will follow up when work is complete.

[Dave Noll]

Just curious if you got your Motorhome fixed yet ?

[rognelson777]

Update, New plugs, wires,distributor cap, rotor and problem is gone. I OHM'd all the old wires and plugs and all matched the new wires and plugs.

I guess something was breaking down under full load.

Used over the weekend towing in virginia and all is well. Other crew members could not believe the difference.

side note, when checking fuel pressure at idle, it may be low, so give it a little rpm and it should come up to spec range of 54 to 57psi. Mine was 47 at idle but as soon as I touched gas pedal went to 54psi and stayed there, even under load.

thanks, class racer

[Ed Wright]

Next time somebody has an issue like this if you have somebody with a Tech2 scan tool ride with you and watch the mis-fire monitor. If missing it will show it and even which cylinder(s).

[Keith 944]

good ideas, my 99 454 m/h does the same thing intermittent miss. changed plugs, wires, cap etc. ran great for year, think it is due again...

[Ed Wright]

Originally Posted by Keith 944

good ideas, my 99 454 m/h does the same thing intermittent miss. changed plugs, wires, cap etc. ran great for year, think it is due again...

I have found a lot of that is dirty injectors. And no, pouring something in the tank won't fix it. LOL