Poor Performance/ killer Gas Consumption

Hello, I wonder if someone one here has some suggestions to help me out, I don’t trust mechanics and I do most of the work on my car.

Three months ago I bought a 96 Eclipse GS DOHC 2.0 non turbo for $1500; I thought it was a great deal because the interior was in GREAT! Shape although the driver side had been hit and the red door had been replaced with a black one, not to mention that, that side of the car still had visible frame damage, the engine looked as it had never ever been serviced and the owner didn’t even know what a spark plug looked like. All in all the test drive was incredible under the circumstances.

The first thing I did was a complete tune up, replacing the PVC valve, spark plugs (Bosch Platinum 4’s) and performance wires, air filter ,flushed the engine, Oil change, checked all hoses, checked and replaced all other fluids added Engine Restore and fuel injector additives. (had issues finding fuel filter, so skipped it for the time being) It ran great for a while.

My car is now running poorly for the past month or so, not to mention its guzzling gas like nothing else! it has no pick-up or power, When I’m stopped at a light and accelerate, it lags and sounds as if its going to burst a spark plug or something lol..and I swear I literally see the fuel gauge go down. I replaced the fuel filter two weeks ago, the old one was sooooo clogged that I thought; :grinyes: “that was the problem for the bad performance” but the problem persists:banghead:

Today I turn the car on after a 30 mile trip and it beeps 12 times. Does anyone know if the car was throwing out a code of some kind? And perhaps give me some suggestions as to how to improve on my car’s performance/ power?

Thank you all so much.

Hi welcome to forum, did you do the engine compression test ? The fuel filter is under the battery, or under right rear passenger side.

Have you replaced the O2 sensor? That could be your problem.

Update: I went out to the car to check the trouble codes using the ignition switch ON OFF ON OFF and finally ON within 5 seconds and this is what I got; 1-2-5-5 neither one of these number codes are in the book not 12 nor 55 ….the check engine light paused 3 seconds between each number, this code method only has two digits, I’m assuming that two two-digit numbers were given, I repeated this process 4 times and had the same result.

Have you replaced the O2 sensor? That could be your problem.

Nope, I havent replaced the O2 sensor, I didnt think to do so until I received a CEL on the matter..... however, I am now trying to figure out what the codes I received are and if one of them has anything to do with my O2 sensor...read the reply update on my post, Thanks.

Hi welcome to forum, did you do the engine compression test ? The fuel filter is under the battery, or under right rear passenger side.
Nope, I have not done an Engine Compression test but I will study the procedure and attempt it.

Nope, I have not done an Engine Compression test but I will study the procedure and attempt it.



Autozone and like stores allow you to rent out tools from them. You can always see if they have a compression tester that you could use. It's a very simple proceedure. And infact they might be able to assist you at the actual store.

Autozone and like stores allow you to rent out tools from them. You can always see if they have a compression tester that you could use. It's a very simple proceedure. And infact they might be able to assist you at the actual store. Great, I've borrowed tools from them before; I’ll call and ask, Thanks

Nope, I havent replaced the O2 sensor, I didnt think to do so until I received a CEL on the matter..... however, I am now trying to figure out what the codes I received are and if one of them has anything to do with my O2 sensor...read the reply update on my post, Thanks.
O2 sensors dont throw codes most of the time

O2 sensors dont throw codes most of the time

yup, I think they throw code after they fell off. My friend honda did that, over 250k miles, same o2, until it fell off.

Well yeah, it will throw a code if it breaks or falls out but if you wait untill then to change it you have other problems

I second the o2 sensor diagnosis. It will make your car run sluggish and basicly give you the worst gas mileage possible. Replace that with one from Auto Zone (they are cheapest there from what I've experienced) and see where that gets you.

I second the o2 sensor diagnosis. It will make your car run sluggish and basicly give you the worst gas mileage possible. Replace that with one from Auto Zone (they are cheapest there from what I've experienced) and see where that gets you.

Thanks, I will definately try that. I was already reading about the replacement of the O2 sensor.

Do you NT guys have an upstream and a downstream o2 sensor? Just my own curiousity...

And dykepepsi, what the hell are those things in your avatar?

Do you NT guys have an upstream and a downstream o2 sensor? Just my own curiousity...

Yes

Do you NT guys have an upstream and a downstream o2 sensor? Just my own curiousity...

And dykepepsi, what the hell are those things in your avatar?
they are just pride rings in water 'you know? cuz Im a "Dyke"( That means; I'm a chick that likes chicks)

I dont think any of us made the connection that you were female

I dont think any of us made the connection that you were female

Thats all good and now it's known.

Also, those bosch platinum 4's...arent those the one that have 4 "lips" to them? the ones that do not get gapped? If so, change those and get a new set of spark plugs that have to be gapped.

Also, I third the suggestion in getting a new o2 sensor...(its most likely the upstream one. Does your car blow out black smoke at WOT?

Also, those bosch platinum 4's...arent those the one that have 4 "lips" to them? the ones that do not get gapped? If so, change those and get a new set of spark plugs that have to be gapped.

Also, I third the suggestion in getting a new o2 sensor...(its most likely the upstream one. Does your car blow out black smoke at WOT?

Yes my spark plugs have 4 ground electrodes and they come gapped, channel 4's are made with four points so the spark can find the quickest and best route of conductivity, but some cars don’t run good with platinum 4's and it seems my car is one of them, I’m going to take your advice. The car has never blown out smoke at wide open throttle. Thanks for the info.

Yes my spark plugs have 4 ground electrodes and they come gapped, channel 4's are made with four points so the spark can find the quickest and best route of conductivity, but some cars don’t run good with platinum 4's and it seems my car is one of them, I’m going to take your advice. The car has never blown out smoke at wide open throttle. Thanks for the info.

I would suggest NGK Iridium IX's. They run excellent in my car...but you could always be safe with the standard copper NGK's.

I would suggest NGK Iridium IX's. They run excellent in my car...but you could always be safe with the standard copper NGK's.

Yeah I used NGK's on my Mazda MX-6 and they were great...I think I'll try them on my Eclipse,:grinyes: Thanks.

they are just pride rings in water 'you know? cuz Im a "Dyke"( That means; I'm a chick that likes chicks)
Ahhhh, I see now. Sorry if I offended you, totally didnt mean to.

Change the fuel filter and rear O2 sensor, both of them together will cause the worst unbelieveable fuel mileage and cause you car to run like absolute hell.

Code 12 means that your battery was disconnected within the last 50 key cycles (probably to try and clear the codes), and
Code 55 is the "end" code, it means that all of your codes have been cycled and the self-coder thingy is done.

Change the fuel filter and rear O2 sensor, both of them together will cause the worst unbelieveable fuel mileage and cause you car to run like absolute hell.

Code 12 means that your battery was disconnected within the last 50 key cycles (probably to try and clear the codes), and
Code 55 is the "end" code, it means that all of your codes have been cycled and the self-coder thingy is done.

You’re awesome, thanks. Over two weeks ago I did remove the battery as I was looking for my fuel filter. Out of pure laziness, I haven’t tightened the + battery terminal and I have had to get out of the car, open the hood and push the battery cables down. Believe me, I've been meaning to get around to it.

So, if I am not getting a CEL on the O2 sensor, wouldnt it make better sence to not replace it? I did replace my fuel filter, next I plan to replace the spark plugs to NGK's.

Ahhhh, I see now. Sorry if I offended you, totally didnt mean to.

In no way did you offend me, It's all good.

Change the fuel filter and rear O2 sensor, both of them together will cause the worst unbelieveable fuel mileage and cause you car to run like absolute hell.


I disagree. The rear O2 sensor simply monitors wether the cat is functioning or not. It doesnt have much if anything to do with fuel trims like the upstream sensor does.

So, if I am not getting a CEL on the O2 sensor, wouldnt it make better sence to not replace it? I did replace my fuel filter, next I plan to replace the spark plugs to NGK's.

Like was posted earlier, you will not always get a CEL when the o2 sensor takes a shit. It has to be completely shot or missing for you to get a CEL usually.

When you replace the plugs, don't forget to adjust the gap to around .048-.052"

Like was posted earlier, you will not always get a CEL when the o2 sensor takes a shit. It has to be completely shot or missing for you to get a CEL usually.

When you replace the plugs, don't forget to adjust the gap to around .048-.052"

Well, that O2 sensor will have to wait but I will definately have to get the NGK'S and gap them.

I disagree. The rear O2 sensor simply monitors wether the cat is functioning or not. It doesnt have much if anything to do with fuel trims like the upstream sensor does.

Completely my fault, I meant the front O2 sensor, but see if the fuel filter helps first.

Also, I third the suggestion in getting a new o2 sensor...(its most likely the upstream one. Does your car blow out black smoke at WOT?
The O2 sensor only has input during closed loop operation. WOT automatically puts the ecu into open loop, and disregards the O2 input. :2cents: Air filter, plugs, wires, front O2 sensor.