I have a 97 civic lx that has some issues. It is throwing a lean code. I have changed the fuel pump, filter, water temp sensor, sparkplugs and the wires. I have installed a cold air kit as well as a header. My gas mileage has gone to hell. the weird thing is that when the engine is cold it runs fine, but when it gets up to running temp it has no power it idles rough and if you are driving at a constant speed the car falls on its nose but if you either give it more gas or let off the gas the power comes back. I have had the fuel pressure as well as the timing checked and both are fine. Both me as well as my mechanic are stumped. If any one has a suggestion it will be appreciated.

 

have you tried swapping out o2 sensors with another car to see if maybe thats your problem?

 

I was told that an o2 sensor would throw a specific code.

 

When i read you were running lean and having bad gas mileage, that was the first thing that comes to mind. It wont hurt you to try borrowing someones o2 sensor for a quick 15min test to see if that fixes your problem. Won't cost you a dime either if you know someone with the same setup as you.

Also maybe you've got some dirty old injectors. What is the mileage of your car and what motor are you running?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kKdARIAN &raquo;</TD></TR><TR><TD CLASS="quote">When i read you were running lean and having bad gas mileage, that was the first thing that comes to mind. It wont hurt you to try borrowing someones o2 sensor for a quick 15min test to see if that fixes your problem. Won't cost you a dime either if you know someone with the same setup as you.

Also maybe you've got some dirty old injectors. What is the mileage of your car and what motor are you running?</TD></TR></TABLE>

Good advise!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CDMNG &raquo;</TD></TR><TR><TD CLASS="quote">I was told that an o2 sensor would throw a specific code.
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not always. if the o2 has completely went to crap it'll throw a code, but sometimes if its just on its way out...no code will show.

also, perhaps its an ECU issue?

Anyone think it might be staying in open loop mode?

 

I have 178000 miles on the car. I also use injector cleaner regularly.