Toyota Repair: 1989 Camry suddenly running rough, jumper wire, power steering pump

Question
Hi.  For the last month or two, the check engine light will go on after driving about 5 minutes and will stay on for varying lengths of time with no noticeable change in the performance of the car.  Last night, I went to a restaurant for an hour.  On the way there it ran perfectly.  I came out, it started fine but ran rough ("missing") and seemed to have a bit less power coming close to stalling at lights/stop signs.  No extra smoke out the back.  Had new timing belt 3 years ago, top end rebuilt (valve job) two years ago, new ICU, coil and rebuilt distributor last year.  Power steering pump replaced last week.  The suddenness of the problem (separate from the check engine light) is what surprises me.  Any ideas?  Thanks so much!

Answer
It may be a good idea to find out why the check engine light comes on before doing anything else, this can be done by getting the trouble codes stored in the computer, locate the diagnostic check connector under the hood and put a jumper wire between the terminals TE1 and E1 with the key on, the check engine light will blink giving the codes, it will be a two digit code
( a code 25 would be two blinks followed by five)let me know what you find out.