Gas pedal STIFF

Here's a new one for me. 302 EFI, AOD. Drives fine, runs good. No shifting issues.

Gas pedal is like a ROCK and takes CONSIDERABLE effort to press. I replaced replaced cable with a new ATP cable, cleaned the throttle plates, lubed the springs and the TV cable, even replaced the gas pedal with one from a 6 cyl truck. With the cables disconnected I don't feel any binding in the throttle body from worn bushings.

I'm starting to think it's either the TV cable or the valve at the transmission. It actually starts to make my leg hurt after just a few minutes of driving. The truck only has 106k on it. It is an absolute chore trying to drive and I have never ever felt any other EFI engine with a pedal this stiff. What else can I check? It does have smooth action and does not feel as though its binding anywhere. Its just STIFF. It's bad enough that I honestly don't even want to drive it.

How about disconnecting the TV cable and operating the throttle?

I'm guessing this truck is new to you by the way you describe this issue. you did not say "it started to do this"
certainly, you could reach over and work the throttle with it not running and feel the effort it takes. then disconnect the trans end and test again
but does the truck have cruise control? I would start by removing the piggyback connection to it at the throttle cable.
in order for the drag to be inside the trans that would mean the tv is binding. not very likely. it is internally spring loaded in the direction you are trying to move it. the cable has an opposing spring to keep the internal one in check. these two keep the cable, lever, and valve very in sync with the valve body which is full of fluid hopefully. more apt to leak then bind.
I'm sure it's possible for the tv cable itself to be a drag whether from rust /corrosion inside the sleeve but I have not seen the condition myself yet. maybe in the rust belt it has been more common.

Definitely hand-operate the throttle lever from under the hood, as the others suggested. My gas pedal had a similar issue and it wasn't until I did this that I noticed the PCV tube from my driver's side valve cover was run just where the lever needs to move. If the air cleaner housing was tightened down just so, the tube would press on the back of the lever preventing it from moving properly.

Not saying this is your exact case but maybe you'll see what's blocking it "from up front"...

I'll have to disconnect the TV cable. Operating it by hand I feel nothing binding and nothing is hitting it. With the TV attached it feels smooth. Just stiff. No change by removing the cruise control cable. It just feels overly stiff. I've never felt one this tight in any of the injected trucks...it feels like it's got 3 of the stiffest carb throttle springs you can buy.

then i would recommend disconnecting both ends of the tv cable. the lower end is on a ball stud. the upper on the t post. then operate the cable from the upper end checking for smoothness and resistance. the lower end has a corrugated rubber cover covering a load spring to hold the internal tv spring in check. the internal spring will put tv pressure way high and not modulated while driving if it is disconnected at the lower end. it will be low and not modulated if disconnected at the upper end. DO NOT DRIVE IT THAT WAY!
if you do than we will be glad to have your business here at transmission masters .

I'll definitely check that cable. I've also been told to take the e clip off the throttle shaft and clean that so we will try that and report back after the new oil pan, u joints and lift kit go in this week.

not a body lift I hope

Nope. 4 inch suspension lift, just enough to clear 35s. Body lifts annoy me lol.

what gear are you going to put in the axle/s? I'm guessing 4.56 but I haven't done the math.

doing the math, I think 4.31 is the correct gear ratio to keep all other parameters correct. however that does nit compensate for added weight or rolling resistance. it may still feel heavier than stock and you may find yourself pushing on the gas pedal even more.

Leaving the gearing alone at 3.54s. Itll turn them but it isn't going to like it 🤣. Some day I may straight axle swap it and gear but for now it's just a daily driver that needs to look sharp.

it's going to drive like it's always taking off in second gear! you will fight to keep it in overdrive on the highway! and the transmission is going to wish you left that extra truck it is carrying back at the house. do NOT leave the tv cable loose as you will very likely cook the trans if you do. get a trans cooler made for towing as the trans WILL generate more heat.

Truck has a factory trans cooler already. XLt Lariat. Had a few setup like this. More worried about getting the rest of it fixed. Oil pan replacement today and was greeted with sludge and a super loose timing chain...that's priority.

how many miles are on the existing chain?
I hear crazy numbers sometimes and I also hear people say that I'm crazy for just changing them at the 150k mile mark. you can have 10 degrees play in the chain by then and they never go back. it is preventative maintenance in my book. one e150 I had in my a/c business I had three chains in. original, then at 150-155, then at 300-310. it had 408k on it when I sold it to the next guy who continued on. this was a stock, fleet 1995 5.0 and never had a seal broken other than the front cover and pump.

Someone has been in it before and put a double roller in it and that's the bad one. Motor has 107k on it. Has a hellacious ticking once in a while that i suspect is the chain slapping the case.

I would be concerned that it may have a bit more miles than what was told.

Given the condition if the rest of the truck I'm inclined to beleive it