Key on the fuel pressure holds 62psi, when I turn the engine on it drops to 52psi at idle. When driving at WOT the fuelpressure holds steady 60psi, if I take my foot of the throttle it's steady at 50psi. But when resting my foot on the throttle holding it at crusie speed and 1500rpm the fuel pressure fluktuate rapidly between 50 and 60 psi, it is at this time I feel the blazer as sluggish.

One more thing, when I turn the engine OFF the fuel pressure goes up to 60psi, 15 minutes later it's dropped to under 10psi. This is a sing of a leak arn't it? It's also more sluggish right after startup, making me think that the leak might be at the injectors. Filling the cylinders with fuel.

http://www.youtube.com/watch?v=tyxkNFkYqDA

 

That rapid fluctuation makes me think that it actually is dropping lower than 50psi and is what is causing your problems. The next step I would take is to pop the upper plenum off and have a look inside. You can also pull off the MTV (manifold tuning valve) which is located under the plastic trim cover on top of the engine and look in.

 

Thanks for the answer. Yes, this must be it!
I checked the timing again with AE and it never reads a missfire.
If my destributor infact was off a tooth, wouldn't it missfire?

Everything is now changed and the engine feels fine, but low on power under the circumstances that I wrote about in the first post. Cruise speed and around 1500rpm.

I changed my FPR last summer, but I did not change the o-rings on the nutkit and injector lines when I took apart the CPI.
AND the fuelpump is a cheap aftermarked one!

I think I will order the complete tank with fuelpump and sender preinstalled( the tank has been welded at some point and won't last much longer), a new fuel filet and a new CPI.
That should take care of it

Thank you so much!