1990 5.0 misfire issue
 

hey fellas, a bit about the car to begin with: 1990 LX 5.0L, basic bolt ons, GT40P heads

The car runs like a dream when the engine is cold, but once it's hot I can hear a slight misfire at idle. Then when I try driving it, it stumbles and misfires constantly.

The timing is steady at 10deg, and I've had it anywhere from 10-14 with no difference. It doesn't ping, and it doesn't bog down when I hit the gas. It feels like the engine is still making power, its just very choppy as it accelerates.

Fuel pressure is steady at 40psi (no vacuum) and 32psi (with vacuum), and all injectors are firing. New plugs/wires/cap/rotor.

I've pulled the error codes from the ECU and the only thing I noticed was a code regarding the fuel EVAP carbon canister (which has been removed and the fuel tank vented). The EGR system is also removed (due to GT40P head swap).

I've driven the car for a long time with no problems since removing the EGR and EVAP system, until now.

I'm stumped!!!

A side note: every once and a while when I turn the engine off I can hear a ticking noise that lasts for about 10seconds then dies. This sound is not coming from the injectors or the ignition system.

WTF!