Luis de Prat

Here's a mysterious situation which I can't figure out.

The car runs great in long gears on the highway, but on short gear changes it has the occasional "hiccup" or hesitation.

The fuel filter was replaced last year, as well as the spark plugs. The ignition control module is about 4 years old, and the alternator was just fitted with a new Bosch voltage regulator. The DME relay has also been changed out, but the hesitation remains. Also, last time I checked, the TPS "clicks" when I move the throttle lever.

I'm looking for possible causes and can't pin any down although the symptoms suggest an electrical problem.

Your suggestions are much appreciated!

theedge

Any obstruction of the throttle cable or throttle assembly? Theres the hose clamp that can get in the way if its rotated too far one way.

Luis de Prat

Good one. It's hard for me to check, as I currently don't have access to the car, but I'll mention that. Thanks!

Steve in New Hampshire

I got rid of an annoying hesitation when I replaced the O2 sensor...when was it last replaced?

-Steve

Fishey

Mine was also the o2 sensor..

Right around 5k in any gear my car would just Pooop with tons of hesitation!

Luis de Prat

Oooh, the O2 sensor is a very good suggestion. Thanks to all!

BTW, which model of O2 sensor does the S2 use?

TIA

Steve in New Hampshire

...from Paragon with the 'official' Bosche wiring kit. Was very simple to splice in to the existing wiring. Check their site for the Bosche part numbers for your S2...

-Steve

Luis de Prat

Well, we replaced the O2 sensor on the S2 and the problem is still recurring.

I'm suspecting the ignition control module or the coil.

Any other ideas would be appreciated.

Fishey

coil could be the isssue...