1997 Civic been sitting 2 years

I recently purchased a 1997 Civic EX with only 57,000 miles. I think it has been sitting for around 2 years (it had moved 21 miles since the title last changed). It drives fine, but seems to have minimal power until about 3000 RPM, at which point it feels like I hit powerband on a 2-stroke motor. I've driven it about 300 miles.

I have replaced the spark plugs and fuel filter. I changed the automatic transmission fluid.

Given that this car has been sitting for so long, what are the likely causes of the poor power at low RPM? Could it be O2 sensor? How about dirty fuel injectors?

Thanks for your input.

So, I've tried a few more things to get my civic running like i think it should. But, first a few more details. I've now run several tanks of gas, and fuel mileage is around 25 mpg. Seems too low for a civic (and I tend to drive like an old grandma). So far I have 1) replaced spark plugs, 2) replaced wireset, 3) replaced cap and rotor, 4) replaced fuel filter, 5) changed the transmission fluid, 6) changed the pcv valve, 7) checked the MAP sensor (seems perfect), checked the throttle position sensor (seems perfect).

I was hoping that driving it with some injector cleaner might help it out a bit, but I'm still feeling sluggish between 2k and 3k rpm. I have been wondering if this could be an O2 sensor problem. So, i checked it. The wierd think is that my Haynes manual says that when the vehicle is started and still cold, it should output a constant voltage between .1 and .2, but mine gives me a constant voltage of around .9. Then after a minute or so, it starts to fluctuate nicely between .1 and .9. I posted a video of my test over on youtube. Here is the link. Can somebody tell me if the haynes manual has it right, suggesting that the constant voltage of .9 is an indicator that my o2 sensor is messed up. Or, is the haynes manual wrong?

Here is the link to the video: http://www.youtube.com/watch?v=yEg5gM4WOKU

Thanks for your help!!

Did you change the air filter?:dunno:

The existing air filter looks really clean, so I haven't changed it. But, since I'm basically changing everything,i'll go ahead and replace it while i'm at it.

I did end up replacing the o2 sensor. I just figured it couldn't hurt. No difference.

Does anyone know if the aftermarket PCV valves work very well on a civic? The PCV valve I put in (from Autozone) had a 90 degree bend in it, and the OEM I removed didn't. Everything seemed to fit fine. I just purchased an OEM PCV valve from Honda thinking that i'd rather have the real deal, but I haven't replaced the aftermarket one yet because I thougth I'd wait until I change the oil again so i can get at it easier.

Also, what would be the symptoms of dirty injectors? Could it still run smoothly at high RPM, or would the engine be running rough at all RPMs if it were a fuel injector problem? I've been thinking of getting a set of re-manufactured injectors and putting them it, but not too giddy about spending the cash if i don't have to.

I just checked my mileage and it is up to 30 from 24 before I started making these posts -- so something made a difference. But, I'm still not convinced it is running exactly the way it should. Next will be to replace the aftermarket PCV valve with the OEM PCV valve, and to replace or remove and clean the fuel injectors.

Here’s another dumb question, did you check your tire pressure? Running low pressure will decrease your gas mileage. Also, you’re millage is pretty good. What are you expecting in terms of gas mileage?

I'm pretty happy with 30 mpg. I was expecting at least 30 mpg when I got the car, so when I first checked the mileage, and was getting around 24, I was a bit surprised. I figured this had to do with the poor power in low RPM i could feel. As I said, I'm still not convinced that the car is running perfectly, but it does appear that the changes I've made so far have made a difference. I would like to be getting 34-35 MPG highway (most of my miles are highway). Maybe i'm not being realistic for this car. But, i was getting around 32-33 on a 99 camry automatic with 4 cylinder engine, so i figured this car should get at least that. Who knows.

I'm a real stickler in terms of tire pressure, so no problems there. I also put in a new air filter, even though it didn't appear to need one. But, a new air filter is a cheap fix, and now I'll know how old it is.

I think the last obvious thing i could do is clean the throttle body and injectors. I'll probably do that sometime soon.

Hell, you just gave me something to think about now. I’ve owned my car for almost 100,000Mi now & never thought of cleaning my injectors.

So, it has been really hot outside, and the bad gas mileage is back!! It seems like the hotter it is outside, the less power I have, especially at low RPM. The engine temp is never fluctuating, but with outside air tempurature going up, i have power going down. Has anyone ever heard of something like this, and what might cause it?

Thanks!

hotter air is less dense, which means less oxygen, which means the car will cut back on fuel to maintain a safe AFR. less gas and air = less power, less power means the car need to work harder to get going which in turn gives you worse gas mileage

EDIT: i REALLY hope you changed the oil first thing when you got the car also...

hotter air is less dense, which means less oxygen, which means the car will cut back on fuel to maintain a safe AFR. less gas and air = less power, less power means the car need to work harder to get going which in turn gives you worse gas mileage
I think this goes beyond that. An example. I sort of rolled through a stop sign when it was about 100 degrees outside, then gave it gas to accellerate. I got almost no response at all, like it was completely flooded or something.

EDIT: i REALLY hope you changed the oil first thing when you got the car also...
Yes, oil and filter were the first things I changed. The engine really appears to be in beautiful shape (no leaks, etc). I just keep thinking that i should be getting better response/mileage out of this thing. Do you think the intake air temperature sensor could be malfunctioning? Or would I get a check engine light?

there def could be something more to the hot air theory... but you WILL notice a big diff in mileage and performance in warmer weather, esp if you have the AC on...

As far as increasing MPG... double check tire inflation, change plugs and MAKE SURE they are gapped (they say they are pre gapped for you, but are never even close), plug wires, distributor cap and rotor.. etc..

i know youve done some of these things, but im just going through a quick list in my head

As far as increasing MPG... double check tire inflation, change plugs and MAKE SURE they are gapped (they say they are pre gapped for you, but are never even close), plug wires, distributor cap and rotor.. etc..

I've done all the things you mentioned above. I checked the resistance in the intake air temperature sensor last night. It did not seem to be working correctly. Autozone didn't have one in stock, but will have one today, so that'll be my next step. We'll see. . . .

Well you've covered most the obvious stuff.
first,
I would check the valves and make sure the gaps are right.
And while you're in there check out the cam real close
for any lobe wear.
second.
I would check the compression and verify that
the rings and valves are ok.
If all that checks out I would verify timing,
both ignition and the timing belt.
Also you might want to get a pressure gage and verify the fuel
pump pressure. It can do strange things like that.:smokin: