Hey..... I inherited a 1990 Lumina with a 3.1 motor.... I have the service records of the car and the injectors were replaced with rebuilt injectors which I found out to be a common procedure. The car is not driven much anymore, but I started reading about the injector problems enough to research a bit about using fuel injection cleaner and the advantages/disadvantages of using these products. Bob the oil guy seems to have done the most research on this and stated that it is not just the injectors you have to worry about, but will the chemicals used in certain products affect other parts of the fuel system; IE gas tank fittings..... and the answer was yes.... The best product for cleaning injectors, was the "Gunk" brand, but, later, he discussed the negative effects of this on the fuel system itself..... So... as usual, there are 50 different opinions on the subject.... care to add yours?

 

if you are talking about products that are added to the tank. Use it at every oil change and you will be fine. Problems can arise when its used to frequently.