posted 10-26-2023 03:51 PM                  

While trying to find out the misfire problem I replaced the #4 ignition coil, #4 fuel nozzle, and all spark plugs. Also replaced PCV valve. Ultimately the PCM had bad coil inside it and that cause the misfire. Since then I get about 150 miles to the tank.

Do you think one of the above parts is causing poor gas mileage or did I inherit a new problem? The above parts were ordered from Rock auto. I have checked all my connections multiple times since the repair and all the hoses are connected. The car performs just fine and have gotten code 414 twice. (Coded 414 is an evap code)

I have been tempted to by an automotive smoke machine to look for any cracked lines. I know the car is 24 years old and hoses can rot away but where to look can be difficult.

Anyone have any suggestions or thoughts?

posted 10-28-2023 09:05 AM                  

quote:

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Originally posted by USCGRetiredAMT1:
My MPG's before - about 20-21 MPG
MPG's after - About 16-17 MPG

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Curious are you buying fuel from same station?

If you are buying higher ethanol % of fuel or winter blend that can effect your gas mileage

On the road my 99 has gotten 20-22 mpg, around town 16-18 mpg

So the mileage you are getting is very similar to what I have gotten in the 43,000 miles I have put on my car

I understand you feel a big difference, but a lot of factors we don’t know

Where you are buying fuel

Where are you driving

Type of driving

If it is apples to apples comparison then yes sounds like you could have a change

Filled up my 2001 recently & in the 500+ miles I have put on it since getting it & checking mileage since gas gauge is different than my 99. Had been getting high 14 to low 16 mpg…… but last tank showed in 12’s

Tried to think of reason it might have changed that much. Hasn’t idled long periods, didn’t drive any different than before, so next spring will see what kind of mileage I get. But when it gets to 1/4 tank in 99 or 1/8 tank in 01 I buy gas

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Larry Mayes