this is an 05 access cab 4x4 4.0 6 speed with 100k with no mods to speak of. there is a surge when i accelerate strongly. I don't know if surge is the right word but the truck will pause for a 1/2 sec or so then accelerate smoothly, then pause breifly then accelerate smoothly. does this in most gears but doesn't do it if i accelerate gently. also will not do it in cruise control unless going up a long hill and the truck needs more gas to keep it cruising at that speed. drives very smooth at a steady speed. rpms do not drop during the pause.
also, idle will dip down to 500ish get a little rough then climb back to 800ish at a stand still after warmed up. No other things on like the air conditioner. Is this normal. its not bad just noticable.
the previous owner said he replaced the 02 sensor, TPS, MAF, changed the oil and filter with royal purple, tranny and diff fluids just changed. he also said the acceleration surge was always there, changing all the sensors didn't change anything. I ran a bottle of sea foam through the gas tank. It had a bit of a rough idle to it to begin with so I sea foamed it, worked well but then the idle flucuation began.
any thoughs greatly appreciated.