what is causing it to run slightly rich and backfire at times and seem like it hesitates some?

1987 FORD MUSTANG
166,000 MILES
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MANUEL81
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It has a vacuum leak from the brake booster. It idles erratically. No engine mods. Does have long tube headers with the o2 sensors. Haven't checked timing but I don't feel
as if that's it. Any help would be greatly appreciated.
Sep 15, 2011 at 2:19 PM
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CJ MEDEVAC
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FIX VACUUM LEAK!!!!

WANNA SEE A CHANGE? TEMPORARILY PLUG OFF VACUUM TO THE BOOSTER!....'COURSE YOU DON'T WANNA DRIVE IT LIKE THAT!...BRAKES WILL NOT FUNCTION CORRECTLY...MIGHT NOT BE WORKING RIGHT NOW, WITH THE LEAK

THE MEDIC
Sep 15, 2011 at 3:02 PM
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MANUEL81
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I fixed the vacuum leak n it does run better. I have also changed plugs, wires, cap, and rotor. Also have set the gps at .98 volts. I still have a problem with it backfiring thru the intake. It only pops back once or twice n that's it. Only does it when engine is cold andk it may only do it 2 or 3 times a week. What gives? Im fixing to bypass egr n use an egr simulator n its place. Any help is greatly appreciated.
Sep 27, 2011 at 8:02 PM
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