i have this weird problem with me car ive posted about it becuase but the problem is that when my car is really cold and sits for a long time and i go drive it it runs perfect...once it warms up a little it runs like **** and starts misfiring and popping so i the o2 is bad then how do i check and see if thats my problem and where is the o2?

 

Use a laptop and Datamaster or Freescan and see what the voltage looks like. Verify that it starts running shitty only when it goes into closed loop (ie using the O2's). Or, borrow someone else's O2's and see if it helps.

 

your O2s are in the Y-pipe one on each side just get under the cr and look you will see them going into the top of the Y on each side under the manifolds. and if you have a 96 and up you have 1 after your cat.

 

can i just unplug them and see if that fixes the problem?

 

i unplugged the o2 and it still misfires at like 2500 and up so what do you guys thing the problem is? when its cold it runs fine once it warms up it runs it starts missfiring at lower rpms and then when i turn the car off and get back in it like 10 min. later it misfires even lower but when i let it sit for a long time it will misfire in the higher rpms 3,000 - 4,000 rpms? i dont get it

i thought it might be my opti spark but now im not really sure?


grrr

 

No, you can't unplug them. Is your check engine light on? When an O2 goes bad you should see black smoke from the exhaust, power loss, even backfiring. When at normal operating tempeture, shut it off, then restart it. Does it turn right back on, or does it hesitate to turn on..like you have to give it a good crank. Also at an idle does your car rev like normal, or does it hesitate up the rpm band.

 

i didnt notice black smoke my friend said i shot out some flames the other night tho and soemtimes it doesnt start as fast as other times there isnt any check enhine light on even after i unplugged it there is alot of power loss misfiring and backfiring when i come down on rpms and sometimes it idles at like 1500 rpms when i stop at the stop sign or something but if i sit here stopped it will drop after a little

so unplugging the 02 wouldnt fix it? it would just be the same as if the 02 was bad or what?

 

::bump::

 

::bump::

 

lol, of course you can unplug them. wtf?

 

yeah if the O2 was the cause, unplugging them should have fixed it. If it didn't then that's not the problem.

I would check the ICM, some people have had problems with that overheating and causing problems. I can't really think of much else that would run differently warm, maybe a clogged cat?

 

i dont have any cats do you guys think its the opti or something else?

 

i'm having exactly the same problem, only my SES light comes on anytime I drive on the highway. I've been thinking either O2's or fuel pump.