2000 olds van 3.4l engine started ticking Top end? Started suddenly last weekend. 220 000 klicks. timing belt slipped a tooth???

When did you last change the timing belt? If the belt slipped a tooth it could cause your issue. I would do a compression test of all cylinders to see if they are good. Any major variation would indicate a possible timing belt slip. Be advised that this is an interference engine and if the belts breaks or slips too far, valve or piston damage can occur.

Re-check the timing, the ticking might be a timing problem.
Hope this helps.

Most probably... All these modern DOHC engines have interference designs that play havoc when belt fails... valves can collide with piston or between them too. To check without opening engine, you could remove timing belt cover and timing belt, and carefully rotate one cam to feel if it binds or not. But engine starting points to a jumped tooth on belt reinstallation (bent valves would not even allow engine to restart! Amclaussen.

Just a thought that the belt could slip if the tensioner did not locate properly. Seems too coincidental that it is not related to the timing belt.

check compression on cylinders, if it is low you may have the timing belt off by a tooth or more

When installing a new timing belt, I always rotate the engine by hand (or rather wrench) before trying to start and recheck the timing marks at least twice to make sure the belt hasn't slipped a notch. Since the engine with which I am most familiar is an interference type, I am very cautious with it; one tooth off and it won't rev but three teeth off and it results in bent valves.

I don't want to be a prophet of doom but it sounds like the timing belt jumped a tooth. If it did the noise you heard would have been the valve touching the piston. If it went another tooth the engine will not start. You need to check the timing, correct it and try and start it. If it either locks up or won't start you probably have a bent valve.

Yes, could have slipped a tooth. Procedures and marks are posted at link below. You may need to sign up for free account.
http://www.autozone.com/repairinfo/repairguide/repairGuideContent.jsp?pageId=0900c1528026660c

what happened sound very much like either you slipped a tooth on the timing belt/chain or the it broke. the first clue is the back fire, and then the no start. your going to have to take the cover off the timing chain to see if this is the case. i would imagine that if it isn't broke but it doesn't start then it slip the gear. if you have not done this kind of work then i suggest find a friend to help or take to a good shop