Fuel Injection problems of the 1998 GMC Safari

In Feb 01 the dealership fixed a rough idle low power condition by using a high pressure top end engine clean called pro tec. This service is not called out in the maintencnae section of the owners manual and is not authourized by gm. Seven months later in October 2001 the same problem occured again. This time the dealership replaced all of the injectors due to "leaking' and also found a leaking fuel pressure regulator p/n 17113203 that was then replaced. I believe the servce in March caused these problems, and that the inventory usage on the injectors and especially the fuel pressure regulator should be for a recall. The pro tec engine service should be investigated to see if it is a safe maintenance practice, which I believe it is not, and can cause dangerous operational problems with these Safari vans. Plus the over all cost was over a 1000 dollars. Dt.

Injection cleaner failed on three occasions.