idle drops too low!!!
 

my mustang not running right ... now when i put it in gear the rpms go down to about 500 or so and it almost dies, it is loping, and when it is in park it idle about 900rpms it is a 1987 GT automatic I cleaned the idle control,intake manifold,got new tps,egr is good,put new vac lines...hmm anyone have this problem before?could it be a bad throttle bodie or fuel pump..fuel press.set at 41

Re: idle drops too low!!!
 

Check for vacuum leak, and check voltage in your tps, try for .95 .99 or so.
If that doesnt work, try reseting the ecu, and then turn in the screw on the side of the tb.

Re: idle drops too low!!!
 

Might sound silly but throw a new air filter on there and if that doesn't work, you can bump the idle up a little bit. Nothing like ignoring a problem to make it go away! lol Check your timing, make sure it's still where it needs to be and that the dist is tight. Another thing to look for is for burnt/melted wires on the exhaust. Have you tried pulling any codes?