I could really use some help figuring out what's wrong with my car. It's a 2002 Accord w/ automatic 3L v6 and just over 100k miles. It's been acting up probably for a couple months now.

Symptoms:
1) < 20 MPG no matter how it is driven
2) Hesitation at low throttle. Will eventually slam into action as more gas is given. Does not seem to be lacking power after getting past the initial acceleration

What I've done so far:
1) Used lots of injector cleaner with multiple tanks of gas
2) Replaced air filter
3) Replaced spark plugs; old ones did not appear to be gunky or scorched
4) Replaced pre-cat O2 sensor
5) Checked for suction leak; difficult to tell for sure, but the hoses appeared to be fine
6) Went to O'Reilly's and used their ECU reader; no codes, and 8 of 8 'readiness monitors' okay on first read; 3 of 8 monitors okay on subsequent reads with no more info; not sure what to make of this...

Thanks!!!

 

Hesitation at low throttle: had same exact issue, turned out to be the fuel pressure regulator - it was low by 0.5-1psi. Worked fine past a point.
Low mpg: air filter??
When you replaced the plugs, did they look light brown and dry?
Brakes dragging?

 

"Hesitation at low throttle: had same exact issue, turned out to be the fuel pressure regulator - it was low by 0.5-1psi. Worked fine past a point."
Gotcha. How can I check this?


"Low mpg: air filter??"
Forgot I replaced that. Added to the list above.


"When you replaced the plugs, did they look light brown and dry?"
Yes. They were dry but not scorched.


"Brakes dragging?"
Nope. But I am wondering about the idler pully. It's squeaking a little.


Thanks for the reply. Any other thoughts?

 

Fuel pressure: what I did was build me a pressure gauge, using a cheapo Auto Zone air pressure gage, a T fitting and some fuel hose and clamps. Used it for many fuel pressure repairs, so I had it in my garage. I opened up the fuel line in the engine bay, before it gets into the fuel rail. Remember, I have a 2.3 liter 4 cylinder - so your config will be different. Before I did that I was trying to locate my fuel filter, found out there's none for my car. If you have one, that will be a good check.

Other check is the coolant temp sensor - that sends the engine cold/warm info to ECU. There's a resistance range to it, I believe there should be a check procedure in the repair manual - maybe there's one on this forum??. You check it cold and warm and see if it falls in the range. That will give you the low mpg also.

 

Clegane, if you find a fix to your gas mileage problem, would you post up the solution?