I recently purchased an fuel injector kit from IPD for my 92 volvo(110,000 miles). How challenging are the o-rings to put on injectors? Do I need to replace them as part of tune up? Is there anything I need to be concern with if I do attempt. Please advise.

This is a real good time to have your injectors professionally cleaned, and flow tested, look in the yellow pages under, carb cleaning, diesel service, fuel systems etc.
I pay $20/injector.

Before removing the injectors blow the dirt out of the area around the base so it won't fall in. A straw will do if you don't have compressed air.

If you need to reuse the plastic caps on the ends, warm them up with very hot water before removing, or they will break. Do one at a time so you always have a good one to refer to.

Use petroleum jelly on the o-rings and the recieving holes or you may damage the o-rings when installin the injectors, more is better than less
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88 765 w/2stage boost & G-valve (TO.)