[masraum]

Originally Posted by Henry Schmidt

If the car you are inquiring about is an 84-89 Carrera, you can adjust the ECU for lower fuel quality. There is a rheostat on the side of the ECU (a yellow knob with a triangle slot ? memory is fading) that will retard the timing about 4 degrees. It's easy to change and can be reset to normal when the fuel quality is restored.
Cheers

But if you want to try this, make sure you know what each setting is. IIRC, there are 6 settings of various timing and fuel richnesses. It's not necessarily as straight forward as just turning the knob one click in a specific direction.

Originally Posted by Kurt V

A stock U.S. 3.2 engine was designed to run on 87 octane. Says so right in your owners manual.

Not all of them. My old '88 said 91 was the minimum, IIRC. 3.2L cars had higher compression ratios than the 3.0L SC. The ROW 3.2L cars were 10.3:1, I can't remember if the US models were 9.3:1 or 9._:1, but it was more than the SC which is why the 3.2L cars used higher octane fuel. (I think my manual or gas door sticker said 95RON(Europe) / 91 (R+M)/2 (US Spec))

Also, in '87 I believe the cam timing and also the ECU mappings were changed from the early 3.2L cars.

"Changes in the fuel map & chip programming from October 1986, further improved the power to 217 bhp (160 kW @ 5900 rpm) for North American delivered cars..."