I have a 1990 Ranger, 2wd, At, 2.9L with 162 k. Occassionally the check engine light will come on and the engine will bog for a second or two. This only seems to occur in city driving. Also, while sitting at a light, it may suddenly increase rpm to 1500 for a few seconds. Could this be an Idle Air Control problem? If so, where is it? Thanks

It could be any number of things. There is a way to read whatever code is being thrown if you have an analog multimeter, but you'll need a book to show you how and what the codes mean -- or you could take it to an old-time mechanic or a dealership and ask. Some places charge a fee for computer work, which this qualifies for, but I'd think it'd be worth the extra $20-$40 if I was planning on hitting the 200K marker.

Thanks so much for the help. Does the need to be on while they are checking it? Sometimes it doesn't come on for days at a time, especially as the days get colder.