Replacing TPS on 16V engine
 

This procedure isn't in my workshop manual, so a couple Q's:

1. Am I right that I'm going to have to pull the fuel rail and intake manifold off to do this job? Is there a write-up somewhere? Clark's just says to remove the tps and replace it.

2. What other parts will I need? Intake manifold gasket, I guess, but anything else?

3. What else should I do while I'm doing this? I've already had the injectors cleaned, and I'm replacing the vacuum lines at the same time. I'm trying to solve a stumble on acceleration.

As always, thanks for the help.

Unfotunately, I believe you are right - you have to remove the IM to change the TPS on the 'S'. While you're there consider R&R-ing the ISV. And write up any issues you have for me since I'll be going after my ISV before next winter.

Have you tested your TPS? I don't see how that would cause your stumbling symptoms.

R&R-ing?

I haven't tested the TPS yet. It's so tight in there I thought I'd have to pull it to test it, and if I have to pull it, I figure I might as well replace it while it's out.

The Clark's website lists stumble on acceleration as a symptom of a bad TPS. I've been chasing this problem for a while, so I'm ready to try anything at this point. The car's had new rotor, cap, plugs, wires, new fuel filter, probably a few other things that I'm forgetting.

you should be able to remove the 4 bolts on the throttle valve to get access to the TPS. But if you need to replace the vacuum lines, might as well pull the intake.

R&R - remove and replace. You can test the TPS by first ensuring you hear the click when you pull the throttle cable a little. If it clicks, then you can check the switch electrically at the DME connector.

If Clark says so - I beleive it. I guess if the idle switch sticks closed, the DME will use the idle fuel map while not idling?

Rick - were you actually able to remove your throttle while on the IM? Seems quite impossible to me.

I think I pulled the intake X 2, since I too needed to replace all the vacuum lines and then later idle stabilizer. I wish the intake for the S was made like the S2 which puts everyting up front and not tucked in the back.

Does the 944S use a throttle-position SENSOR, or throttle-position SWITCH? It makes a big difference to the answer to your problem.

All the the 8V 944's use a switch. It's highly doubtfull that a throttle-position SWITCH will cause the problem you describe. The 968 uses a true throttle-position SENSOR, which will cause the problem you describe. I have no idea whether the 944S has a switch, or sensor, but i think it's a switch. If so, you should look elsewhere, like your air-flow sensor.

It's a switch like the 8V's. Two switches, really, idle and WOT. Nice to learn that the 968 has a sensor - thanks Mike.

Well, I'll do the TPS anyway, since I'm going to have the manifold off to do the vacuum lines and replace the gaskets.

I'll check the air flow sensor, though, too. Thanks.

Oh, if you've got the IM off, absolutely replace the TPS regardless of what any diagnostics tells you.