89 2.3 EFI DIS Processor or Wiring?

[Houston_Locksmith]

Hi, I've got and old 89 Ranger, 140/4 cylinder with DIS and 8 spark plugs.

I was driving along yesterday and it stated to jerk a little and the MIL came on and then everything cleared up. A few hours later the MIL came on again and it jerked, blew black smoke (gas), and the idle dropped to 600 or so. I drove home and let it cool off.

I checked for codes KOEO/Continuous/ and there were none. I then called it a night and this morning tried to do the KOEO test again using my voltmeter. No luck. The needle stayed at 12 volts when I cut the key on. I also noticed the fuel pump running continuously with the key on instead off cutting of after one or two seconds. I also noticed the left 4 plugs aren't firing while the motor is running. The MIL stays on all the time too.

Knowing the processor controls the fuel pump voltage through a feedback loop where the processor senses the fuel pump feed voltage through terminal 8 telling the computer the pump has power, am I correct in assuming the processor is bad and needs to be replaced because it is what cuts the fuel pump relay off and it isn't doing that with the KOEO?

I disconnected the processor and checked to see if there was a short to ground between the ground and the fuel pump relay ground circuit and it was OK. Is it a common problem for these processors to go bad?

I do have a 1500 watt inverter installed. The inverter got hot the other day and shut down. After it cooled off it was fine. The truck started acting up about 200 miles later.

Thanks everyone.
Ed