I searched this topic to death, i found out why these may go off individually but i can't figure out why they would all go on outta the blue. The car has been getting shitty gas mileage since december. I attributed it to the cold weather. But it is around 20mpg highway, so i know something is wrong. I changed out the thermostat and my car heats correctly but i am still getting the terrible gas mileage. Then after timing my car, my check engine light coems on and code 3, 6, 10. Car is hesitant, boggy, idles rough, and again gets horrible gas mileage. I had a chipped p28 running on chrome, so i swapped it out for the stock ecu, and same exact problems. I do have a VAFC2 installed, but it hasnt been touched for months, and pretty much just serves as a fancy gauge. So i know that is not the culprit. Also, my lights seem to flicker more with the rough idling of the car. Any help would be great. Every topic on here is dead or they say they fixed it with no explanation. I can always smell coolant too when i pop the hood or walk next to it after driving. Never any spots on the ground from where it's leaking so don't think there's a leak.

Summary:
- Codes for Intake air Temp, Coolant Temp, and MAP.
- BAD gas mileage
- Rough Idle
- Car hesitant in low gears low rpms
- When i let off the gas it jerks the whole car
- All three check engine lights appeared out of nowhere

 

I bet all of those sensors share a common ground or power source and the wiring for your vafc (mingled in with the MAP sensor) has come loose. Just a theory...

 

i'll have to trace

 

just check the wire colors at the sensor

 

wires from the vafc harness we're frayed a ways from the ecu so it was hard to find, but fixed it!

 

nice! glad it worked out