Hi:

My 1990 760T was up for an e-test prior to reregistering this month. It failed by a lot:

ASM2525 TEST (at 1678 RPM, and "Dilution"=17.7)

HC ppm: limit is 58, reading was 178
CO%: limit is 0.32, reading was 5.99
NO ppm: limit is 652, reading was 449.

Curb Idle Test (at 758 RPM and "Dilution"=17.7)

HC ppm: limit is 200, reading was 172
CO%: limit is 1.00, reading was 7.68
NO ppm: n/a

It is garaged in the winter, had almost a full tank of high octane gas(with stabilizer) at time of test today (not sure if that matters). Only second time out of my garage in past month. It runs very well, and only had a slight issue at warm startup later today with the RPM dropping and it stalling when going from Park to Reverse. Also generated a 1-1-3 OBD code first drive out after winter. Reset, and code did not reappear today.

Any thoughts appreciated. I am wondering if best plan is to pay Volvo dealer $200 for their diagnostic to confirm source of issue.

Would a non-Volvo dealer (e.g. Ford) be a reasonable alternative to diagnose/fix also? Would Volvo have any special equipment/expertise to diagnose faster/more reliably? I dont really like my Volvo dealer, and can get into a good local Ford dealer faster.

Thanks!
SM