[HoodStrype]

Whew- That could be a lot of things... but only after the car heats up huh? Makes me think electrical. Like chrismic101 says, if the car is stock you need to:

-These are basic for any car-
Wires
Cap
Rotar Button
Plugs
Belt
The Ground Cable Mod (I'll look for a site on that it works miracles!)
Vacuum Lines
Check Hoses for wear/leaks
Check timing
In your case before you check the timing check the control module on the distributor (Autozone will do it)
If engine has been built before check the Fuel Pressure or put in a guage... mine likes 37-39 at idle.



and if you got the $$$$...
Alternator
Battery
Solonoid (Cheap)
Throttle Position Sensor (25 bucks- good to know it's new)
Air Bypass Valve (aka Idle Air Control $70)
EGR Valve
Anything prone to screwing up on a Fox Body that I forgot

Oh yeah, Like I said I used to have an 86, so I can go ahead an tell you that the Throttle Body, Intake and Heads are different on that car... they're a little smaller than the 87-93- But that front end looks better than any of 'em! Good choice guys! Holla if you need anything