Can the throttle position sensor be installed improperly? Check engine light came on, I took it to a shop and they said tps was bad. I purchased one from toyota and after replacing the truck runs bad and smokes??
Are you sure it is a 1989? I did not think that throttle position sensors or check engine lights had been invented in 1989.
Does it have a flux capacitor?
Throttle position sensors can be installed wrong but on an 89 vehicle it may not make a difference. The mechanic was guessing. An EGR valve that is stuck open would be a likely cause of that problem. Somebody will have to check the plugs, timing and compression in an attempt to diagnose the problem which seems to be getting worse.
I don’t think it would be possible to install it wrong due to the way they’re made. Sounds to me like you may have installed a bad part where a good part was. Put the old one back on and take the “new” one back for another new one and see if it works. Also check that it’s completely plugged in.