Gunnar24

Thanks for helping!

I have spent a few hours looking here for a solution, but in every thread the OP didn’t respond with the solution, super frustrating!

I have a 99 2.3cl and first noticed a small chug at 60mph in 5th gear, then my CEL came on. The last few days here in MN went from cool to super humid and rainy. I pulled the codes and got P0170 and P0171 and I am getting terrible gas mileage.

Does anyone have experience with this? Is it my O2 sensor, my fuel pressure regulator, bad gasoline?

Thanks again!

Gunnar

phootbag

You need to determine what is causing your fuel trims to adjust to the limit. Most cases this is caused by a biased oxygen sensor.


You need to monitor the primary oxygen sensor voltage. If you can confirm a steadily low oxygen sensor voltage, inject propane into the intake stream. If the oxygen sensor doesn't respond by showing an increase in voltage, the sensor has likely failed.

Gunnar24

I filled up the tank and put fuel additive in, cleared the CEL, seems to be running okay.
I'll update this thread when I find out more.

Thanks,
Gunnar