I am curious if 7th gen I-4 owners notice that if you have the rough idle and great mpg, or do you have smooth idle and so-so MPG's. I notice that a lot of posters complain about the diesel like idle.

My idle is very smooth, not quite as good as my Old Zetec Focus but very smooth. But my MPG's are so-so. Could the smooth idle-so so mileage be due to a richer fuel air mixture. I get about 26-27 MPG average. Sort of a luck of the draw situation? :dunno:

I get great consistent mileage around 33-34. I have a rough idle about 50% of the time, or at least the idle seems a tad rougher than what it usually is.Not sure what everyones definition is of rough idle. And this is "rough" idle with AC off, not to be confused with AC on rough idle.

My idle varies from "is this thing on?" to "Wow, it feels like the engine of the city bus".

My MPG also swings from "Haha! Take that civic!" to "WTF?!? I should have been hot-rodding a V6 to get this kind of MPG!".

I can't really find any correlation between the two, even with looking at the car with my OBD scantool. It is a good thing that you're trying to find a link between them - we might find something.

:lmao:

my cars feels the same way.... sometimes, especially after a long drive, i wonder if the car stalled out on me or not; so quiet, including the valve noise non-existant

other times, the whole car vibrates..... it's a common "indicator / dummy light" to tell you that she's running fine.... :nuts: :lmao:

my car doesn't need lights on the dash to tell me what she's doing. the rattles, vibrations, and spongy pedal feel at startup, all tell me that she's working as normal..... :yes:

I would concur with all who have answered. I do notice this too that sometimes my idle will be rough, sometimes silky smooth. Weird. Also, I notice that sometimes my idle will actually be better with the AC ON! Sometimes to even throw my theories off is that when I press the AC button, it doesn't even make the pop sound. Strange!

actually the only time my car has a "rough" idle is when it first starts in the morning, cause the engine is cold.

after i take it down a few streets the engine warms up and i dont even notice the idle


as for mpg, im not really sure, as this is my first car and ive only filled the gas once so far myself, although it does seem to be consistent to the posted mpg that was on the window sticker.

(oh ya i drive an I4 automatic 2006 accord)

Most of the time, it's difficult to tell that the engine is running. Sometimes, though, especially after long highway trips at high speeds (75+MPH) or if it's below about 50 degrees F outside, the idle is choppy. Mileage is pretty consistent around 29-34MPG.

Hmm my idle is pretty smooth, but When the AC comes on it does seem to vibrate a bit. I have just over 5000 miles and my miles per gallon seems pretty bad, hopefulley it gets better. But I floor it almost all the time so I suppose that makes a big difference.

the thing just shaking like crazy, and usually if I stop at the traffic light. the rpm sometimes drop to 750rpm and just shake me up even I turns off the AC. and my mileage is terriabl. part of the reason is I use to cruise at least 75 on freeway and I floor it most of the time.
But I have tried keep the rpm 95% of the time below 3000rpm, but the result is not significant better...

well, if that's the case, time to go back to your old driving habits.... :yes: :cig:

btw, have you tried to reset the ECU on the car by disconnecting the battery for 30 minutes?

just a thought.....

Mine feels like past accord inline four's so I'm not worried....anyone remember GM's QUAD 4 from the nineties? Now that was rough...

Never noticed, so I guess its smooth. I generally get 30.x mpg with mostly city driving. I got 36.5 through WI on the way to Chi-town doing 75.

the thing just shaking like crazy, and usually if I stop at the red line. the rpm sometimes drop to 750rpm and just shake me up even I turns off the AC. and my mileage is terriabl. part of the reason is I use to cruise at least 75 on freeway and I floor it most of the time.
But I have tried keep the rpm 95% of the time below 3000rpm, but the result is not significant better...

so you screwed up your transmission by flooring it to much?

nope, my tranny work fine.
I should get the v6..the 4cyc just not enough power for me :thumbsdow
but i like honda 4cyc :notworthy :notworthy :biggrin: :biggrin:

so you screwed up your transmission by flooring it to much?

ops. I mean stop at traffic light..not red line.. :lmao: :lmao:

My '05 I4 auto gets rough idle from time to time without the a/c, and you can feel it much more with the a/c on. The mpg's are pretty decent - high 20's in mixed city/town, low 30's on highway....

andy

Our Accord has idled the same since purchase. SMOOTH!!! MPG is always in the epa area. This with the wife driving it 99% of the time.

Its bumper to bumper warrenty is about gone. Taking it in this weekend to have some stuff looked at on it. All cosmetic and function. No mechanical issues.

After thats all done and we get thru the 36k mile mark. I will index the plugs and start turning it in to our car. Other little mods to follow. We have looked in to maybe super charging it. Or doing some head and cam mods. None of the things im looking at will destroy its good mpg MUCH. But might make the car a tad more fun to drive.

Mine averages 18-22 MPG, A/C on, four 4.6-mile trips to and from work each day. I got 28.5 MPG on my only road trip so far (car is 3 months old, 1,900 miles) with 90% highway, 10% city, A/C on. Generally easy on the gas and brakes, but occasionally put my foot in it. I'd have to classify mine as "smooth" (as far as 4-cylinders go). My former car was a 6-cyl. Buick - very smooth and quiet. The only noticable vibration is right off idle when accelerating - but that's just feeling each cylinder fire since there's only 4. Idling with or without the A/C and above 1500 RPM seems impressively smooth. I don't abuse my vehicles (often, haha), but I don't frequently focus on fuel economy. I tend to focus on comfort, performance, and cleanliness, and maintenance. It's not worth it to me to practice highmiling just so I can save $8.64 on my monthly fuel costs.

The idle comes and goes. Sometimes real smooth and other times a little choppy.

I did notice this:
I use only Mobil gas and one day I tried Shell and my milage fell from 31 to 25. Went back to mobil after a couple of fill ups, milage is back up to 31.

My friend bought the same car around the same time. He uses what ever is out there and he was complaining about how horrible his milage is. I know there are may variables when calculation MPG.
He switched from what ever to Mobil and he is now getting in the 27's and it continues to increase.
Interesting. :yes:

just filled my tank and reset a trip timer - ..now someone tell me whats the capacity of the gas tank, as it was not fully empty when i filled it.

just filled my tank and reset a trip timer - ..now someone tell me whats the capacity of the gas tank, as it was not fully empty when i filled it.

Now that your tank is filled and your trip odo reset, drive for another period of time and fill the tank again (from the same station/pump if you can, and letting it shut off the same way both times), and THEN calculate the MPG by the miles divided by gallons.

Why not use the capacity of the tank? Because it won't be accurate - the tank volume is not exact, and sometimes you get gas in the filler and sometimes you don't. Using the same station and/or pump and letting it shut off the same way each time is about as accurate as you can get to measure a single tank's MPG....

So, you've got the first part done, now drive this next tank and do the same thing over, and you'll get an accurate reading...

andy

I,m getting 21-24 MPG with poor throttle response (must step on accelerator hard to get thru 2nd/3rd gears). Driving is 50/50 hwy/city. Very disappointed in combo of fuel economy & power. I bought the car 2 mos. ago pre-owned with 9K on the clock.

2005 EX-L I-4 Auto

I,m getting 21-24 MPG with poor throttle response (must step on accelerator hard to get thru 2nd/3rd gears). Driving is 50/50 hwy/city. Very disappointed in combo of fuel economy & power. I bought the car 2 mos. ago pre-owned with 9K on the clock.

2005 EX-L I-4 Auto
People don't notice this stuff on the test drive? :dunno:

Just fill a full tank of Mobile 89. and do some gentle driving. with all acceleration below 3500rpm. I will see what sup on my car.