I'd check the AMM for starters... Don't know a whole lot about them, but they seem to often be the cause of strange idle problems.

After that, check for vacuum leaks. They can do all sorts of crazy things to your idle.

Check the hoses going into the intake manifold. See if they are plugged up with sludge. Renew them if they are.

Good luck!

(Side note, I just took a trip to Cleveland my self a couple of weeks ago... It was amazing how few Volvos I saw while there, at least compared to my home town Portland. I think I saw a grand total of 8 Volvos, and only 2 of them were 240s.)
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If you listen to the radio in Portland, OR, you may know me as "Portland's Favorite Soul Brother!"

Holy Cow!

Not to side-swipe your thread, but my 90 745GL non-turbo is suffering the exact smae deal. In the same order sorta.

Rock chip in the window (just below the wiper blade) has now spread up a hair and over about 9".

Couple weeks ago, it didn't start on it's usual 2-3 seconds. Now it's like 5-6, especially when it's first started.

Idles fine on crank-up, but in P or N revs will not fall below about 2000 until another gear is selected. (with a bit of a thunk LOL)

Dang that's wierd.

BTW, ben simmering here for a couple years, but don't post much. Brick is a two-owner car, 218k miles, serviced at the same shop since new, B230F, Automatic, driven-every-day, kid transporting, silver over burg leather, window regulator blown, solid, reliable and safe machine. Best money I ever spent car.

Will be interested to see what the pro's think about the long crank.

Thanks in advance,

Mike R

90 745GL, 218k miles, B230F, M46, stock except for radio
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'90 745 214k