I have an '89 Volvo 740 with 230k ; I'm the third owner, as far as I can trace, I got it February this year. It has been a great car until recently. It ran really smooth, and the motor was strong and even. I decided to clean the MAF, and I used the CRC MAF cleaners and followed the directions. However, as soon as I reattached it (after letting it dry for 15 minutes), my car idled really rough, and stalled out just sitting in park. I followed the FAQ, and when I disconnected the MAF, it idled smoothly, although it didn't have a lot of power when driving. I tracked down a refurb Bosch unit from Schuck's, and once that was installed, the car idled smoothly, although it stalled out when changing from P to R or D, or when I came to a stop, unless I gave it a little gas; about enough to keep it at 1100 RPM. I decided at that point to take it to a mechanic. I was told that the throttle body was really, really dirty, and that was cleaned. When I got the car back, I was told that the front oxygen sensor was dead, and the fuel injectors needed cleaning. However, while it runs smoother now, it still stalls out at stops and when shifting unless I give it gas, which I didn't have to worry about before at all. If anyone has ideas on where to start looking for problems, that would be a big help.
Thanks.