Back with more issues. Looking for assistance from the friendly fox crew.
Car will run perfect for weeks then all of a sudden after the car is warmed up one day it will begin to shudder and misfire under acceleration like the fuel is cutting out when you press down the gas, kind of like if you hit the rev limiter but with longer intervals. If you play around with the pedal a little it will come out of it for a couple sec and go right back to it again. It is so bad the car will not pull a hill, huge loss of power. If you let of the gas the idle will some times move up and down, but never to the point of stalling. Park the car, fire it up next day it’s like nothing ever happened, it will run great for a day a week a month then do it again.
This happens irregardless of the amount of fuel in the tank, but only after the car has been driving for at least 30 min or longer.
What I have done so far: Replaced the distributor cap (plugs and wires are good). Replaced the fuel filter. Tested the transfer pump and the main pump per Bentley instructions (amount of flow in a measuring container for 10 sec (transfer) and 30 sec (main) both were good. Verified mechanical timing and distributor timing per Bentley instruction both checked out good. Replaced coolant temp sensor (the right one) with a new Bosh unit.
I did install an air fuel ratio gauge (was having issue prior to installation, figured the gauge could give me insight) I know its not correct as it could be as I am only using a narrowband 02, but its reads ideal or slightly rich when things are in order, and when it is messing up it is reading supper lean that’s why I was thinking it could be a fuel issue.
Not sure what to do now. Trying to get this issue solved as I am taking this car to H20
Thanks in advance for your help!