2.3l engine: timing belt needs adjusting?

[watermellon]

Hi, I need help asap. I have an '89 ranger with a 2.3l engine and distributorless ignition system. The last time i took it for a drive it ran fine. Now it runs rough. It feels like it wants to die when I slow down or stop. It also accellerates poorly and it almost feels like its running on 3 cylinders. I have an inkling the timing belt has slipped but I'm not sure how to check for that or even how to adjust the timing belt if it has slipped.

Also I'm wondering if a leaking vaccuum hose or a bad pcv valve could be the culprit? If so how should I test for those? If anyone can help me, please do, I'd greatly appreciate it. Thanks in advance.