Engine reads bad coolant temperature sensor as well as bad catalytic converter?

EPKIDD221

MEMBER
2007 CHEVROLET COBALT
2.2L
4 CYL
2WD
AUTOMATIC
127,000 MILES

The check engine reads bad coolant temperature sensor as well as bad cat converter and gas detected in exhaust. Changed temperature sensor twice and reads when it wants but has never over heated. Changed cat converter and it didn't even need a new one. For the past week it's been hard to start and smell of gas at start. I changed plugs. For three days check engine light went off run great and temp sensor works now. It's still running good but check engine light is back on. I take a lot of short drives to work and back two to three miles. I just tried sea foam in oil after oil change as well as Chevron Techron for two fuel ups now. Yesterday I found my gas gauge isn't reading right. Filled up and reading a quarter tank shy. Just want some suggestions maybe some help what I should do.

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
42,940 POSTS

First, please clear the codes and then turn the car on to see if there are any codes, if not start the engine and then shut it off and run the codes again.

This guide can help:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

I have seen the EVAP purge solenoid stick open causing the codes and problems you have described. Here is the location so you can see if it is open, (blow through) if so, the valve is bad, and it needs to be replaced. Check out the images (below). Please let us know what happens.

Images (Click to make bigger)