[Jared at Pelican Parts]

a worn pressure sensor will usually cause the car to run WAY rich. YOu can also do a quick check of it by sucking on the vacuum port to see if it's holding vacuum. What happens is that there is a sealed cell diaprhagm ion there that can seperate and trick the computer into thinking there is a false vacuum reading. I think there was a guy on the board that was repairing them, do a search.

as for the TPS, it's on the throttle buttefly. (the black box attached to the butterfly shaft) if you remove the cover, you'll see a arm wth electrical contacts that contacts the printd circuit track on the board. What typically happens is that the printed circuit track wears a flat spot. Sometimes, if you are careful you can clean it, or remove a bit of material to freshen up the track, then very slightly re-adjust the electrical arm to contact it.

also on 1.7's another common problem is that the throttle shaft becomes slightly bent and causes the butterfly to stick in it's bore. This was causing some hesitation and idling problems on my old car. I'm pretty sure this has to do with the way the throttle cable applies constant pressure to the top of the shaft, hence bowing it over time. You can check this by taking off the air boot, then opening the thorrtle by handf then letting it shut quick. if it sticks closed, then you know it's bowed.

I fixed this problem on mine by carefully disassembling the throttle, smoothing the edges of the butterfly and also lightly sanding the portion of the shaft where it sits in the throttle housing. this solved the problem for me.

THere's also the old problem with vacuum leaks. If there are any leaks, it will cause a bunch of problems. When i had my 1.7 i would replace the vacuum hoses every year.