So I bought a 1989 740 Turbo a couple of months ago. However, I've had one significant issue since I've had it. Its an auto trans with 169k miles, and often when I shift into reverse or drive, the engine stalls and shuts off when shifting.

Lately, this has been happening every day. I also notice that it struggles to maintain idle revs, and has shut off a few times while left idling for a few minutes. This problem tends to happen mostly in the mornings when it is first started. The engine usually shuts off after I let my foot off the brake.
I've also noticed that while in park, putting the gas pedal down will sometimes cause the car to choke and shut the engine off, which makes me think it may be bad MAFS. While driving the car seems to shift normally, but this occasionally happens from a stop.

I'm hoping the transmission isn't going bad. Any thoughts? I know there's a way to adjust the idle speed, so I might try that.
Thanks!

 

I'd say the first thing to do is verify the idle control system is working properly. your 89 turbo is LH2.2, so this monitors the engine RPM via the hall sensor in the distributor (LH2.4 cars use a crank position sensor), and when the idle switch is closed on the side of the throttle, modulates the idle air control to maintain the 700 rpm idle. when the engine is cold, the idle should be more like 900-1000 rpm.

I'd follow the troubleshooting procedures here, https://www.volvoclub.org.uk/faq/Eng...tyThrottleBody

there's also the proper idle adjustment procedure there (noting again you have LH2.2)... note that stuff which says "pre-89 only" actually applies to your 1989 turbo too... non-turbos were LH2.4 in 89, but turbos didn't switch until 1990.

 

I think your transmissions fine, you're having a few electrical gremlins you should look into before considering a swap.

Does your transmission shift fine when you're driving? No delays? Reverse still work?

 

The first thing you do is check for massive airleaks. Probably torn hose from MAF to turbo.