Hey guys, a week ago I bought a 2006 mazda 6 V6 115k miles.

I've been trying to diagnose my problem here. These are the issues.

-Delay in throttle response when pressing gas.
-Car seems like it's sometimes low on power when accelerating at higher RPM. It doesn't misfire, stutter, but sometimes I can feel the power drop when accelerating. Some times it doesn't do this.
-Car also seems to be sluggish sometimes below 3k RPM, then immediately picks up. Again, doesn't misfire, just slow.

Other times the car feels fast all around. It seems to vary. It's not a huge noticeable difference when it seems "Slower"

-Car idles perfect with or without A/C on.
-Car DOESN'T run at all when at 1/4 tank gas. It will buck when accelerating, completely stop accelerating and then surge, it will shut off at idle / while driving. I fill it up with gas and everything goes away except the engine light. I have reset the light after filling it up and it comes back on. There has been times that it will go off for just a minute, then I'll accelerate and it will pop back on.

Checked for air leaks with brake cleaner, sprayed a lot, no difference in RPM.

Car puts out lean bank 1, lean bank 2 off idle.

I had the car looked at by a ****ty mechanic. He hooked it up to the computer and he thinks it's the fuel pump but isn't sure. He confirmed the O2 sensors are adjusting data, so they appear to be working, but that's literally all he did. Didn't check for vacuum leaks, didn't check fuel pressure, nothing. I hate some mechanics.
I'm guessing fuel pump too. Just want to know what you guys think before I drop $250 on a fuel pump. No more ****ty mechanics for me, the guy told me what I already knew after I paid him $80 to *diagnose* the problem.

Thanks.

 

Chrisguilday

I didn't read that you found more then 2 DTC's? based on what you just posted you should have at least 2 more I can think of off the top of my head?
But if that is all you got then you have your work cut out for you. The diagnostic problem solving for those is very long. There is no short cut unless you have some experience with a specific problem and know a few short cuts.


There are exact ways to check the fuel pump. NOT by having us all guess at it. That would mean anyone doing so has a 50% chance of being correct... LOL

Maybe next time don't use a "mechanic" but at least a ASE Auto Motive Technician. We like to Bragg/boast about having that status and especially if we are current. We don't guess and there are rare circumstances can not find the problem within an hour. Your in Florida I happen to know there are many ASE's in shops all over that state!

The fuel pump requires for best diagnosis a digital volt/ohm meter and a F/I Fuel Injection pressure testing kit.


Fuel pumps can be found under 200 bucks.
ULTRA-POWERE8794M
CARTERP76310M

 

I never got back to you, sorry. But yes, it was the fuel pump. Thankfully it was easy to install. I bought one online for around $90. Wasn’t familiar with the brand, but if it goes bad it’s easy to replace.

All the signs were pointing towards the fuel pump, and I found a lot of other people reporting that they also had problems when below 1/4 tank and it turned out to be the pump, so that was enough for me.

by the way I LOVE this car for what I paid, only cost me $2600 with 110K miles but it’s in fantastic shape. It’s the grand touring sport with pretty much every option except leather seats, and I kind of like the cloth better anyway. Overall it’s 8.5/10 condition, probably the cleanest first gen 6 I’ve seen.

good to know about ASE though, thanks!