hi, i haven't been able to chase this one down because of the cold temps of the north east on the street with out a garage.it's a eec-iv ,sefi motor with about 300k on it.she's been a very reliable mechanically sound motor with some bad sensor,wiring,or connection issues.it starts on like one revolution and a half.when i let go of the key there is a delayed catch of the ignition as it's still turning some.so it starts great.runs and drives like it's supposed to for it's age and mechanical condition but that changes when it reaches either normal operating temp or maybe hotter ,i don't know because my temp gauge is broken..it doesn't ping under load or blow a hose or blow into the over flow reservoir.i call it hiccuping. as the temp approaches it's hiccup phase it comes in waves of hiccups and then smooths out and progressively gets worse as it heats up more.it seems like it's fighting itself and then counter fights itself to stay running with some mechanical knocking as it tries to smooth out.surging,hesitation,misfiring,etc...when i try to drive it it misfires and jolts so bad as it's shifting that it making my driveshaft,rear differential bang around because there's so much slack in the rear and u-joints.i smell a varnish type of smell which tells me that it's sparking but the cylinders don't have the fuel to ignite it completely.if it were an unburned fuel from a spark misfire then i would get a strong gas smell. so it's not a misfire.it runs good for so many seconds and then runs terrible for some seconds.driving it i feel jolts like i have never felt before even with a bad misfire.i got the following codes.i have had some of these codes for years but it ran fine except for the fuel pump primary circuit fault which is a new one and that is making it run terrible.i can't post an mp4 so you can hear while it's running.i am starting to think it's quite possibly the alternator for some reason because its on the motor and gets hot.i wonder if i should try an output state alternator test or my newest hunch being the fuel pump regulator,that sits on the motor and gets affected by heat..what do you think? any help will do thanks.

 

When we get a series of unrelated codes , usually a ground problem . Check and clean all the grounds you can find.

Also, something else that is common to a lot of the codes is the 5 volt reference voltage that is supplied by the computer All you need to do there is measure the reference voltage at one or two sensors. Should be 5 volts if not check a few of them. If still not there you need to go back to the computer (ECA) and make sure it is coming out of there.

 

Considering the age, I would take a close look at the ECM. Electrolytic capacitors start bulging and leaking and you will get many different fault codes such as you are experiencing.

 

While you are in the computer (ECA) , they used to have a ground problem where the ground in the ECA was interrupted by a cold solder joint or crack in the printed circuit board. If you can, trace the ground coming into the circuit board and look for anything were it might be cracked or corroded.