Mileage drop of 21 MPG - need mechanical advice

[Cd]

Hey - could I just have some really bad gas ?


Hello ? Hello . Where did everyone go ?

No seriously, the gas that is in this particular tank is a couple of months old. What would be the symptoms of having bad gas ( besides not having a girlfriend ..no... no really )

I have added three things of fuel injector cleaner to the car and it seems to be acting up less. In fact, the last couple of days, it has started every time.

I also sprayed some throttle body cleaner into the car as well. Perhaps all of this was just a clog somewhere ?

It still doesn't explain the sluggishness the car has accelerating up to 45 MPH.

Just wondering.

While all of this has been happening, i tried replacing the seals that go between the valve cover and the spark plug chamber. ( There is some oil leakage into there )
I managed to give one of the nuts just a tiny bit too much torque and snapped it off.
The bolt is the one on the valve cover that also attaches the ground to the engine.
I reattached the ground to another part of the engine that is actually attached to the block itself. Just out of curiosity, I pulled it off entirely and the car still started first try.

There is some pressure coming up through the area where the nut broke off, and the seal is going to eventually blow off unless i do something. There seems to be oil leakage around the valve cover gasket, and even some oil around the oil fill cap ( only enough to give that area a wet look ) but everything is snug and tight.

Any advice ?

[Cd]

I should add that the only major change in the car in the last few months, is that i have begun driving the car more often.
I usually only drive around 14 miles once every couple of weeks. - sometimes as little as 3 miles a week of slow stop and go ( mostly 35-40 MPH or less )
Here recently though, I have begun driving and extra 60 or so miles of fast freeway driving of at least 65 MPH.
( Once to twice a week I make the highway trip )

[MGB=MPG]

93 civic eh ?

do you have a shop manual ?

sounds like you need trouble shooting and servicing

check a civic site for specialty help

your choice is to do what you can your self or haul it to the shop,,

shop time needs deep pockets ..
even supposedly knowledgeable shops can have idiots and fools working in the bay..
hard to get good help anymore in the trades.

Hondahookup.com - Honda / Acura Aftermarket Parts, Accessories, Forums, Photo Galleries, Racing, and more!

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chiltons manual is ok i guess
Honda Civic Repair Manual - Chilton, Haynes - 2005, 2004, 2003, 2002, 2001, 2000, 1999, 1998, 1997

Honda Civic Repair Manuals | StreetPerformance.com

good luck

you CAN do it

[JasonG]

How much oil is in the spark plug wells ?
My saturn once had some spilled in there. Drove me crazy figuring out why it was running poorly.
Long screwdriver and a paper towel got it out.

Other hand,
My buddy was having O2 sensor issues with an older Izuzu he bought. Some metering showed voltage between the ground wire and the frame. We ran a wire from the sensor ground to the block and it started purrin like a kitten. Running one can't hurt. Often the ground strap gets oily on the back/bottom of the engine and makes lousy contact.

[Cd]

It looks like the problem is either my fuel pump or my main relay.
I pulled the main relay and it looks fine - no wear or burnt coloration at all.
I would think that the problem would surely be the fuel pump, except that the car drives fine once it is started. There is no hesitation, but there is the lack of power mentioned earlier as well as the drop in FE. *

If I stand next to the engine and manually rev the accelerator linkage to a good high RPM, the car will have a small 'pop' of one of the cylinders not firing maybe once or twice, but it is hardly noticeable and only when i rev it high. The idle is fine.


I tried to start the car two days ago, and there was no 'hum' noise that the fuel pump makes when you turn the key to the 'on' position.
Then today, after pulling the main relay, I put it back in and turned the key. I immediately heard the 'hum' of the fuel pump and knew the car would start.
It did.
I have read about fuel pumps doing this when they get hot, but the pump was cold in both cases. I'm just really hoping that the fuel pump isn't dying.
The reason that I posted was to ask what symptoms to look for in a failing pump.
The symptoms that i have read about on other forums so far sound more like a relay problem, since the car has never stalled, or even stuttered while driving. It just refuses to start at random ( despite hot or cold weather ) like a relay problem.
BTW I checked all the fuses - all good.

* When the car was not starting, I ran a spark test on a couple of the plugs ( hard to do when you don't have help )
It looks like the coil that I just had replaced from the shop i mentioned before is either junk, or the distributor is bad, because both plugs were only giving a weak orange spark. ( but at least it was constant )
This could have something to do with the poor FE, but not a sudden drop like I have had right ?

I know that this is not a car fix it forum, and i thank all you guys for the advice you have given me. I actually have been trying other sources besides here.

I have looked at several honda forums, and I'm really confused, since there are so many things that can go wrong with a car that sound like something else. I certainly trust you guys more that the auto shops that I have called and parts stores as well.
Of course they are going to tell you it is the most expensive part.

Thanks !

[Cd]

I'm thinking that if the car is running fine now, then it can't be tested right ?
Testing anything now would simply show that everything is working.

[Frank Lee]

I've concluded we don't have enough information to diagnose from over the net.

[Cd]

Thanks Frank.

[Hubert Farnsworth]

Could the hesitation be the early warning signs of a plugged catalytic converter? That would possibly at least partially explain the acceleration problem, however why it somehow overcomes this at higher speed I am not sure. It would have been caused by an issue with the air/fuel mixture for a sustained period of time however, which means that the potentially plugged catalytic converter is only a symptom of another problem potentially related to that miss fire you were identifying at high engine speeds when manually controlling the throttle

[Clev]

My understanding of Honda main relays are that they normally fail when the car or interior is hot, with a no-start being the symptom. Usually when allowed to cool, it'll start right up, and I'm not aware of poor running being a main relay issue. You can take it out very easily and ohm it out with a multimeter.

When my coil failed, it ran fine with little throttle, but stumbled badly when the gas pedal was pressed, so that doesn't sound like your issue either. (I went to the auto parts store and they let me compare it with a new one.)

The high revving might just be because you have to keep your foot in it to accelerate, so it's upshifting later.