I think my 90 vert is in limp mode. What items can cause limp mode? I plugged another OMP into the harness and no change.. Do i have to install it? Also i can't pull codes. eng light don't come on.

 

try swapping the bulbs with another one.. the engine light might be burned out or removed . as for limp mode. i drove around on limp mode for about a week . not fun .. you get bucking, hesitation, cant get it over 5 grand,, feels like your running on one rotor.. for me i had to replace both the omp and the sensor , cuz the stock one cracked in half. after i swapped them both out , the car ran like a champ. although . i was able to read the codes from the blinking light code trick

 

Try unhooking the battery to clear the mode. Always works for me.

 

I will try and install a different AFM in the morning. I will check the bulbs tonight... Thanks..