Drove my Monte Carlo from St. Louis, MO to Erlanger, KY (346 miles) and broke the 30 mpg barrier. I made the 6 hour trip in 4 hrs non-stop.

April of 2019 I had new heads and a new head gasket installed. New EGR June of 2020 (old was completely plugged). New tires on front and fresh brakes on front.

Intermittently I get an "intermittent" hesitation at highway speeds. I used a pint of professional grade injector cleaner w/out much noticeable changes.

Also, even with a replacement EGR valve, my check engine light still goes off. The code says EGR.

Any help would be appreciated.

George in Pittsburgh
2004 Monte Carlo
174,000 miles

 

I see no one posted on this. Not sure if it’s relevant still.
1. EGR code I’m assuming is “insufficient flow”?
The passageway in the intake carbons up bad on those, and seeing as how the old one was plugged up that’s where I’d be starting. Use an old piece of parking brake cable or clothes line in a drill and use combustion chamber cleaner and work at it little by little. If the cable doesn’t go into the intake easily it’s still plugged up.

2. That could also solve the hesitation.

3. 30mpg isn’t too bad, you’ve still gotta get 6 more mpg to catch my 3.8’s best economy though 😉 (pre-top swap).

Let me know if that helps you at all.