I havent takin it out yet but ill find out tonight. Ill post some pics when i can get to a scanner. The plugs wires and all that had been replaced. The fuel filter was a little loose at the carb so it could have been leaking there. Ill see what happens.
A disconnected EGR will not cause poor fuel economy, the EGR valve meters a quantity of exhaust gases back into the combustion chambers, since the exhaust gas is inert and will not burn it reduces the efficiency of the engine, this reduced efficiency lowers the combustion temperatures and reduces the amount of NOx emmisions. I am very familiar with the Grand Marquis, they are a great car, but very big and heavy, especially the mid '80's are not known for great fuel economy from new, the problem is more in the cam, compression, and heads.
That is not surprising, but take a close look at your catalitic converter, they will plug and cause very bad gas milage, a good tune-up, make sure the timing is advanced to the factory spec's or even a bit more (to set, disconnect the vacuum advance, using a good timing light increase the rpm until full mechanical advance is obtained, then at that rpm adjust the timing to 34 -36 deg, finally reconnect the vacuum advance). This will usually provide the best milage and power, but watch for detonation and adjust the timing down if any is suspected.
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