'92 SSEI with 179,000 miles
This all started earlier this winter (after using some gas additive for a while - which may be a coincidence). I would be driving down the road and mash the pedal. I would get no downshift and when the car was warm it would sputter and give me nothing. At one time the car even died. My first thought was fuel pump, even though I changed it last summer. I haven't had the pressure checked yet.

Anyway, I thought maybe the filter is clogged from the additive (cleaner), so I changed the filter. That seemed to help some but I still do not get any real power at WOT. My boost gauge shows ful boost (10+PSI) and I do start to accelerate after a time, but I never do get a kickdown - much like it doesn't recognize I've opened it up. Sometimes at higher speeds it will kickdown, but only after a lag of some seconds.

I also changed the spark plugs in hopes that it might help. Three of them were of questionable condition.

Does anyone have any other ideas of what could be causing this? How would I test those ideas? I suppose I need to check on the fuel pressure. I understand that if it drops below 40 psi at WOT, it means there is a fuel pump problem, correct? I am not real excited to go back into the tank. I'll have to wait for better weather fo that, if needed. It'* too cold here at the moment. That'* why I would like to eliminate any other possibilies first. Thanks in advance.

what voltage do you have on your TPS at idle and WOT?

0.428V idle to 4.33V WOT

You mention changing the plugs. How old are the wires and what brand are they?

I think the wires are original, but I am not getting the problems like misfires that bad wires would cause. I just don't seem to have the power I once did. That'* why I lean to fuel problems. I don't have a fuel pressure gauge. That'* why I havn't checked the pressure.