o2 sensor goes lean

o2 sensor goes lean under wide open throttle and than check light shows misfire code.
shouldnt the o2 sensor go rich at wide open throttle. im assuming lack of fuel.

Bank 2 sensor 1 looks to be slow responding or stuck rich. Videos are real blurry cant be 100% because of that might want to have someone hold the camera to the scanner keeping it focused. Also what are the codes, year, make and model of car?

the first code that triggers the light is p306 but continuing driving creates the other codes p305 , p0172 or p0300.

Ok the p0300 p0305 p0306 are misfire codes
The p0172 is a bank 1 rich code

Whats the year make model of car?

In mean time check your spark plugs for fouling and excessive gap, ohm test plug wires if applicable, ohm test injectors and compare to your maintenance manual, ohm test primary and secondary side of coils and compare to maintenance manual. Also look at maf sensor reading at idle, 1500 and 2500 rpm it should read close to the liter displacement of engine. IE 3.8 liter engine should be ~4-6 grams/sec at idle. if it is less or way more try cleaning it with some maf sensor cleaner or a solvent that does not leave a residue that is safe for electronics. If it does not read correctly after that you might have to replace it depending on what injectors ohm out to as well as what you find with plugs, wires and coils.

I think it was p0171 not p0172 plug are clean new . When the misfire occurs the injector goes off to prevent cat damage.

The coils and plugs are new

To answer your question, yes, upstream 02's should go rich at WOT. Default strategy does this.

Check those 02's by causing a rich and lean condition. Vacuum leak will cause lean condition and alternative fuel, propane or brake cleaner will cause rich condition.

Do a snap throttle test, both 02' should equally go rich.

You need to discover if you have a true lean condition or a failing 02.

Don't be a part changer, test first.

A snap throttle doesn't go rich. But if I use some brake clean in the intake it goes rich but it still has that limpy misfire

Carstuff wrote:

When the misfire occurs the injector goes off to prevent cat damage.

What are you basing this on? Not saying you're wrong, I want to understand were you know this to be a fact in your case.

I had scoped the injector on that cylinder using my snap on scanner and the ecu cut the signal to that injector. Now if I shutoff and restart car the signal is back for a good 10 seconds before it cuts off the signal to injector pulse.

That's absolutely how it works. By default, the ecm will reset the injectors pulse at new startup until it again detect the dead misfire.

The history on this car. You replaced the plugs and coils because of the misfire?Did you swap coils and or plugs first to see if the misfire moved?

The coils were bad they were sparking outside the body. Replaced all only one good coil . Plugs were worn just put in new one.
Sometimes the misfire is gone for 2 miles and come back

Are these coil on plugs or a waste spark system.

Could have coil driver problems but intermittent spark... Have you scoped the crank and cam sensors and reviewed their correlation?

The coils are individually per cylinder.
The coils stay sparking during the misfire. Pulling the coils I see the spark . I didn't check the cam crank

Do you have any ignition waveforms for us to review?

I don't have any waveforms. I'm assuming it's good with new coils

If you have constant spark but intermittent injector impulse, I would look at the wiring very closely. Heat and vibration. Look for contact and stress points in the wiring... Good luck and report back.

It seems to be a real misfire . I probed different parts of the injector wiring and the scope shows the same readout of no activity.
Sometimes it's p0300 sometimes its p306 p305.

Have you checked the injector pulse at the ecm?