For foes of government regulation, one action by the Federal Trade Commission earlier this week was the kind of horrible example dreams are made of: a federal regulatory agency criticizing a state regulatory agency for passing state regulations that violate federal regulations.

It all began with an attempt by the State of California to strengthen automobile emission system warranties - a move the FTC claims may result in "substantial anticompetitive effects" in the automotive parts-replacement and service industries.

In a filing yesterday with the Environmental Protection Agency, the FTC said the California Air Resources Board action could have serious side effects that may be illegal under federal law.

The CARB adopted the new emission control warranty regulations last December in an attempt to keep as many automobile emission control systems in working order as possible, thus keeping the air as pollution-free as possible.

CARB, however, had to clear its new plan with the federal Environmental Protection Agency, which, in turn, asked for public comment on the seemingly uncontroversial proposal.

To everyone's surprise, however, the Federal Trade Commission filed comments of the California regulations.

The FTC pointed out, in its filing, that several of the principal aspects of the California plan could have anti-cpmpetitive effects, and may not "appreciably promote environmental aims."

For example the FTC said, independent garages, body shops and service stations selling independent manufacturers' parts now account for an "overwhelming proportion" of the auto replacement-parts and service industries in California.

But the new California plan, the FTC warned, "would encourage vehicle owners to use only original equipment parts and have their vehicles serviced only at franchised dealers."

The FTC said other problem areas in the CARB plan include:

The absence of a provision assuring vehicle owners that use of an independent manufacturer's part will not affect the warranty.

The fact that many of the parts that must be covered by the warranty in question are not primarily intended to reduce auto emissions, but would now have to come from manufacturer-designated stations.

A requirement that a dealer give a vehicle owner a "free" diagnostic check if a preliminary examination reveals a warranted defect. The requirement does not extend to independent stations, where the consumer would have to pay such a diagnostic test.