2.2L Getting Bad Gas Mileage

[98sunfirecanada]

(98 Sunfire, 2.2L Auto 4spd)

Hey guys,

Just lately i've noticed a real drop in my fuel mileage. A month ago i was getting about 500kms per tank, and now i'm lucky if i get 300!

I noticed yesterday that I had only travelled 30kms (I always set the tripometer to track my mileage) and already the fuel gas had moved down considerably (almost 1/8 of a tank!)

Here is my list of things i've done to try to remedy the issue:

-I've run about a gallon of fuel injector cleaner through it in the past month.
-Plugs are new (delco platinum)
-wires are good
-ignition module is brand new (ground wire was cleaned off and greased)
-new TPS
-new IAC
-new MAP
-new TB gasket (cleaned the TB with cleaner)
-checked all the vacuum hoses (no leaks)
-coils are firing properly
-coolant is filled up
-air temp sensor replaced
-coolant temp sensor replaced
-front o2 sensor replaced (2nd one was replaced last year)
-I only use synthetic oil and flush it with seafoam
-replaced fuel filter and airbox filter
-tire pressure is good
-inspected the fuel regulator and it's not dripping fuel out of the vacuum side

I even took the valve cover off and "degreased" it and cleaned the PCV valve that is built into the top. It was pretty plugged with a yellowish gunk. Plus there was some oil laying in the air tube going to the TB.

I am totally confused at what is suddenly causing this car to drink so much fuel!

Two weeks ago i had a P0404 code (EGR range) after my engine began to stumble and jump. So i shut it off and restarted it, and all was fine. The light stayed on for the day, and that night i took off the EGR and cleaned it with TB cleaner. I put it back on and shut off the engine light. It has never came back on, but i'm wondering if i should replace the EGR? Looks like the original.

Any help or ideas would be greatly appreciated.

When the weather gets a bit warmer I'm thinking about pulling out my injectors and giving them a good cleaning, and replacing the o-rings on them.

 

[melsg5]

how many miles on the engine? how did you determine the wires are good, resistance test? did you peform a compression test?

 

[1233fire]

2.2L 2001 Sunfire having this same problem.

Were you able to figure out what caused the low gas mileage?

 

[melsg5]

the thread is over 3 years old, start a new one

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[Jeremy_steven10]

Clean EGR should help, and can reset the ECM I've been told. Unplug negative on battery and pump brakes till it gets hard to pump, leave unplugged for awhile and reattach. Then the computer can relearn your driving patterns. Saw this on you tube. I've tried it, and I saw a little difference.