The car has 203K and has always been well cared for as I personally know both owners since it was new.

Here's what I've done:
Full tune up w/ NGK Iridium plugs
Full can of seafoam in a 1/2 tank of gas
Disconnected EGR
Royal Purple oil change

Update: Ihave since cleaned the IACV, FITV, and replaced the O2 sensor and thrmostat. It's idling smoother, but not perfect yet.

The only thing that made an improvement was getting the new ignition system on it. I thought about tossing in a coil, but i've read they don't go bad too often.

It's also turning around 3k rpm doing 60-63 on the highway. Even though it's an automatic that seems high to me, but I don't know the norm for these cars.

 

Why did you disconnect the EGR? What size rims/tires are you running? What rpm does the car idle at when in park/neutral and in d4 after fully warmed up? Have you cleaned the screen on the IACV? Is the idle rough when the engine is cold or warm, or both?

 

i didnt read what you wrote only your only reply and i guess you disconnected the egr put that back ok then check timing and map sensor connections

 

its a 20 year old car with the original motor. how many miles per gallon were you expecting?

 

3K on the rpm's at 60....I'd figure out why the trans/converter isn't locking up.

 

Is your S or D4 light blinking? Verify the bulbs work by selecting the function. http://techauto.awardspace.com/trans...html#Solutions

The CB TCU is known to have faulty caps and resistors, but in this case I suspect that the NC sensor is either coated in ferrous metal and needs to be cleaned off or the sensor has failed. Pull both NM and NC sensros, clean them off, install new O rings(Honda Part No. 1309-PX4-003 O-RING (16X2.1) (NOK) $1.83), reinstall and test drive again.

 

The rough idle is only noticeable when in gear, hot or cold, and it sits steady at 800 once warm.

Haven't cleaned the IACV screen I'll find how to do the tomorrow.

My D4 light isn't blinkning and I haven't seen an S light.

Where do I find the NM and NC sensors? I take the are input/output speed sensors for the tranny? My suspicion on the RPM was that the Torque converter wasn't locking.

It also sometimes won't accelorate and you have to put the pedal down and get it to down shift to get up and move. As the throttle is opened slowly it will continue to loose power and sometimes back fire until it downshifts.

 

Just found this, thought I'd share:

http://techauto.tripod.com/

Oh, and considering I had a 1983 3/4 ton chevy that got 22 mpg I'd expect more than 25 from this little guy, once the bugs are gone

 

sounds common for an automatic accord to get gas mileage like that on the highway to me. i looked it up for ya anyways
http://www.fueleconomy.gov/feg/bymod...a_Accord.shtml

reconnect the egr. if its disconnected and your idle is rough then its not hurting you. if. you connect it and it gets a rougher idle you have a problem in the egr control system. there should be no vacuum in the hose at idle.

if the idle is rougher then warm then clean the iac. if its rough when cold then clean the fitv(fast idle thermo valve). or clean them both for preventative maintenance

 

25 mpg is good. My 92 Accord was getting 22mpg. My 95 Accord gets 20mpg

 

It seems like these should get better than that. It makes me curious as to what they got when they were new and running at 100%. I read the EPA chart in the link above, but they are usually close, not spot on.

 

The only way someone is going to be getting 25 mpg is if they're doing all highway driving.

 

I do about 90% highway driving, so I guess that why I get 25 instead of 26 I'm going to do all the clean-up that was suggested on here today and check that the lock up solenoid is functioning.

 

I got all the cleaing finished up finally, thanks to all the advice from you guys. I messed with the fast idle valve some and it now idles high no matter what. I think it may have to do with that, but I'm going to adjust the idle screw first.

or maybe the other way around??

 

i get 30+mpg on highway only drives.

 

Can you tell us where these sensors are and what they look like?

 

The only way you can see the N/C sensor is to remove the battery and the mounting plate under the battery. It will be a two wire sensor that is held in the transmission case with a single 10mm bolt.

The N/M sensor is on the other side of the transmission and can only been seen with the left tire removed. It looks the same as the N/C sensor

 

Thanks, hopefully I'll be able to get to those soon.

Today I found a new problem. I got off the highway and noticed my temp guage seemed to be low (pointing at the 3 of D3). as I drove the rest of the way home it slowly rose a tad. Then I parked and let it idle until the temp came up to where the needle pointed at the 4 of D4. So it would seem I have a Thermostat stuck open. To Advance!!

 

A bad thermostat will not let the car properly warm up to temp and will affect the way it runs.

 

Yeah, I know, but for some reason it didn't seem to do it before I cleaned everything up. maybe the FITV had bad air flow before. Since it's not at normal operating temp when I actually get home, the FITV is keeping it at warm up idle. I think I'm going to put in a 195* t-stat.

 

I had this same problem with my 92 accord, trans. was not locking on the highway, or would lockup intermittently. The fix was the thermostat, apparently it was stuck open and running the engine too cool. Which, in turn, would cause the trans to unlock.

 

They are on the right side cover. In the link I provided if you scroll down you will see a drawing of the cover with sensor location.
The easiest way to get to them would be to turn the wheels to the right and look behind the wheel on the right side. You will easily see both sensors.

Had an 84 GMC 1500, those mid 80s GM FS trucks are freaks. They can pull down some pretty damn good MPGs for a brick.Although the majority of them have no power. 3.08 FD with a .7 OD and 28" tall tires = 1600rpm @ 65MPH. A few aero mods could get them up to 25MPG

 

might wanna check out your throttle body might have a bunch of crap on it. that can cause a rough idle. cleaning it might help. dont spend time and money on complicated stuff think simple.

 

I'm up to 27.5 mpg on the highway, call me crazy but I'm still not happy with that. I just did the O2 sensor, which was definately bad. The old one rattle like a noise maker when I shook it. which reminds me if any of you go to Advance for one, make them break out the paper catalog, or make sure the one you get has a "male" connector. The first one I got was right in the computer, but had a female connector, you could plug the new and old sensros into each other!

Oh, and another fact that was posted somewhere else said the oem had a 192* t-stat, WRONG!! It is 78*C (marked on the OEM t-stat) or 172* ferenheit, so the 180* Stant that every auto place has on hand will just fine.