Replaced oxygen sensor but no power
 

I own a 1985/2 955 with 149500 miles on it. The car failed the emision test. My CO was 5.11 and the limit is .64. I had the oxygen sensor replaced. Drove the car home from the shop and it ran great.

Went for a little ride and after the car warms up there is no power. Let the car sit all night and started right up and ran great until it warms up, then again feels like no power.

What's up? Seems like it's running to lean.

Thanks for the input.

hmm.... what were the rest of the numbers like?

O.K.

HC was 230 should be 200 and NOx was 590 should be 1400.

Did not pass the HC but passed the NOx.

well, low NOx is not a problem.

i think the system that is supposed to lean out the engine when it is warmed up is not working and it is actually running too rich. hence, the high HC and the high CO. there is a temp sensor on the block at the front, just below the cylinder head, that you should test.

i am sure others will have things to say.

The system I think was running rich before I got the emission test. The car ran very well that way.

besides running poorly, what makes you think it is running lean?

You give it gas and you get nothing.

perhaps it is an unrelated issue that popped up coincidentally with the replacement of the O2 sensor.

have you tried unplugging the new sensor?

could be running rich. i think I need a new O2 sensor as well. Mine would surge and feel lethargic around 5000-6500 rpms. It runs really solidly and is definitely stronger with the sensor unpluged and it gets almost 30 mpg instead of ~26. Hmm...I wonder if there's even a reason to get a new sensor?

I love having wilk's chip...
dont need to worry about stuff like this!

As I said in your other thread check for a small leak from a cracked header pipe, that'll screw up the mixture.

The reason it runs OK at start up is that it runs on predetermined fuel maps until the engine gets to the correct temterature range then it starts reading the O2 sensor, thats when you start having problems with driveability.

what does your air filter look like?

New 2 years ago.

so, what you are saying is that it is OLD. (depending on miles driven, of course.) i personally don't go over one year without cleaning my K&N.