[Techno Duck]

I think Ted is talking about Jae's place in Miramar. The shop next door does a lot of older Land Rovers and Mercedes.

I agree that knowing what the AFR is doing will help out a bunch.

Does this happen on a cold or hot engine?

Have you checked the cylinder head temp sensor yet?

For dyno places, the Dyno Shop in Santee and JBA Speedshop in Kearny Mesa all have dyno's with wideband (AFR) readout. You could probably just pay for an hour to run the car at various loads on their dyno and they give you a printout with rpm and AFR. The Dyno Shop is where Jae used to tune most of the cars and they do have the ability to burn custom motronic chips.

I'm not sure if the Dyno Shop does much for troubleshooting old Motronic cars but its certainly worth asking. JBA, i highly doubt they will work on it.

An alternative to paying for some dyno time is you can buy and install a wideband O2 gauge and install it on your car. The entire setup would probably cost you the same as what an hour or two of dyno time is. This can be easily installed in a 'temporary' manner, literally with wires taped to the fenders and run into the cabin. For the o2 sensor, there are clamp on brackets that mount on the tail pipe. Or you could just remove the narrowband O2 sensor and do the testing with just the wideband installed. As far as i know, the Steve Wong chip does not use the stock narrowband O2 sensor at all anyhow.