ok i keep throwing a p0172 code randomly, usually on the highway at a constant speed 1 time a week. my cyl #1 (cyl closest to the passenger side of car) is flooding with gas and mixing with oil and pouring out of my pvc valve into my cai. the excess gas is thinning my oil and causing my cyl 1 to loose compression aroud 150 or so. to prove this we poured oil through the spark plug hole and manually cranked the car then removed the excess oil and did a compression the results were 190. what could be causing the excess gas in only cyl # 1 thinning the oil? i have 60 lb injectors so were all thinking a bad injector, bad harness, pcm issue, maf issue (we cleaned and examined it and it looked good) or 02 sensor. the cylinder walls were perfect with no scratches or damages of any kind so that along with our oil test tells us the rings are fine. so any suggestions? ps i was also throwing the p0172 code before i did the 60lb injectors and the new tune. what should i do? what could be causing this? how can i fix it? is it possible to switch the 2 o2 sensors on the exhaust? reason i ask is because the rear 02 is turned off because i dont have a cat. thanks guys

 

Don't you have a head gasket problem......?

 

if you have an intake it will throw that code and the oil coming out of the pvc valve is normal just put an oil catch can on

 

intakes are common for throwing p0171 fuel system lean, not p0172 fuel system rich.

if you have one hole flooding swap injectors around and see if the problem follows the injector. also, check fuel pressure. if you have one hole with bad compression and it sounds like rings regardless if its running rich or not, its going to flood the oil with fuel.

 

Im having the same issue as well I thought it was the cold weather and Im running 1 step colder plugs and I have 60's lb. I was thinking of putting the stock plugs back in to see what it will do. but I also think I have a bad valve seal under high rpms Im getting blow by on the #2 I have a lot of issues right now

 

I got the head gasket replaced. I switched injectors with a diffrent cylinder and the compression in cyl #1 is increasing everythime I check. Do you think its the injector crapin out?

 

sounds like you have an injector going **** up swith it to another hole and see if the problem follows

 

i switched the injectors and the problem did not follow. just so were clear the is no gas mixing with the oil in the oil pan. the oil in the oil pan does smell a little bit like gas but its still black. if i blew a piston ring would the gas back flow into the oil pan? the oil coming out of the pvc valve is white and reaks of gas mixture with oil. what does that mean and how should i go about fixing it? broken injector or blown piston ring? or could it be something else?

 

the pcv valve is in the intake manifold, the hose from the valve cover to the intake piping is the breather hose. if you have oil spewing out the breather hose and it smells like fuel, or the oil even has a small smell of fuel, you have internal engine issues, my thought would be a broken piston or bad ring. a compression test isnt the be all end all, my friends 2.2 ecotec had a broken piston and still had 150psi compression. a better test would be a leak down test, that will tell you for sure

 

we did a leak down test, and cyl #1 leaked into Cyl #4 depending on where the piston was