87 formula 350 all mods in my sig, just recently under part throttle above 2300rpms my car has developed a miss.... i kno its a miss i can tell through the sound of the exhaust and the slight loss in power. i replaced the plugs VG2, mallory wires, MSD cap+ rotor about 3 thousand ago, also had upgraded the coil to an MSD blaster coil and ACCELL ignition modual. the coil and modual have been on there for over 10,000. fuel pressure is 50psi, low temp thermostat and fan switch and a motorvation chip and 8* base timing.... just started over a week ago and the miss is pretty constant from 2300 on up but below the car seems fine, throwing no codes.... and its upsetting when im driving bc the power loss is noticable not to mention the exhaust note change. any ideas on what it could be??? oh also the wires dont seem to be arcing and non are burnt through etc. only seems to happen above 2300 and in overdrive its really noticable.

im thinking cracked cap etc or water in the distributer... if thats the case would i have to replace the rotor/cap and how would i stop the water in the distributer? i dont kno if thats the prob but i checked the plugs and all of them are on good and no arcing between the plugs... just want to kno where i should start.

 

anyone??? this is my daily driver and the miss is killing me.

i did this yesterday to see if it helped with no luck... removed plug wires at the cap, took off cap and rotor and it had slight carbon buildup so i cleaned them all off to bare brass, checked allthe wires and non where burnt etc, removed plenum and set fuel pressure from 50psi to 48psi, i set with vacume line disconnected to 48psi but when vacume connected back it drops to 38psi at idle in park??? also checked TPS an its running at .52/.54 volts so thats ok, throwing no codes but i didnt disconnect the batt to clear the memory... i wonder if i should have, also up in fuel injector cleaner into gas.

when i rev the car in park theres no miss but when im on the road and get on it there is a miss, really noticable in 3rd and 4th. car has noticable power decrease and change in exhuast note sounds like a miss but not a backfire... i need help can anyone help me. base timing was set at 8* i believe and im running a motorvation strip chip but have done nothing to the car and this all started alil over a week ago...

 

another update... i plugged the vacume line backinto the EGR, car actually idled worse and had worse throttle response, so i unpluged it and plugged the vacume line and cars throttle is back etc. also checked timing, im at 10* base with computer bypassed, with ECM plugged in spark advance was advanced to 27.3*!!! at idle in park. other vitals in park are... at idle in park
408mv= O2 sensor
1.72v MAP
1.3-1.5ms injector pulse(1/2 throttle seen it increase to 6+ms pulse)
27.3* spark advance ECM connected at idle

just drove it and I STILL HAVE THE MISS!!! WTF! can anyone help me? its like a hesitation but only happens in drive like 3/4 gear...?????