I'm replacing my fuel filter and also running a high mileage fuel cleaner through system. I need to know if I should run treatment before or after I change the filter. I'm trying to treat excessive gas consumption and hard idle

 

Your vehicle may have something else going on. Low fuel press and volume usually affect performance under load.
Low fuel delivery would not result in high fuel consumption..
Can you bring us up to speed on what kind of routine mai9ntenance has been done ?

What do you mean by hard idle?

 

It fluctuates in idle. I've had a diagnostic done. Said fuel pump is problem, but I'm trying to replace smaller stuff first to clean it up. I've changed o2 sensor (all 4) coil packs spark plugs air filter, still need to clean MAF sensor. Just stuff I can do at home for now. I'll have to take it to shop for pump

 

How many moles on your vehicle?

If you have no power problems, a fuel pump will not solve the excessive fuel consumption problem..

Did you get a copy of the diagnosis results ? If so, please post them here. What will you do after the fuel pump is replaced and you still have the same problem?

Would like to see the data stream info from the diagnostic. When you know what to look for with the data stream info , it can tell you a lot.

Excessive fuel pressure can help lower MPG and maybe some idle performance, but you should be getting some black smoke from the exhaust and the data stream info from the oxygen sensor reading after the converter should be working overtime.Please consider getting another opinion from a different reliable shop.

 

I didn't get a printed copy. I trust this mechanic so I didn't question it. He said o2 sensor and fuel pump. I know I'm having some kind of pressure problem anyway. When I take a sharp left turn, it tries to stall and my gas gauge is all over the place. 50 in gas is still on empty, 20 in gas gives me half a tank

 

Do you keep your vehicle in a garage or does it always stay parked outside ? If it stays outside, it may have a leak that you don't smell.