I have check engine code about misfire in cylinder 4, i have changed spark plugs and ignition wires, after that i reset ECU and was not getting code again, however engine vibrates on idle randomly and cannot hold steady idle RPM, i assumed it was a idle valve issue.

Was driving on freeway for a while at 70 miles per hour however misfire code did not come on, but after taking car to smog shop i had it back, why is that?

I am considering cleaning injectors next, but i'd need to know which exact cylinder on the engine is number 4?

 

Chances are there is a problem with the coil pack. Check it very closely for carbon tracking and fine crack near the #4 cyl.tower.
Looking at the front of the engine (faces pass side of vehicle), #4 cyl should be the first cyl on the grille/headlight side looking from the front of the engine.

 

Thanks for info i forgot about ignition coil completely. I already tossed the old wires already, but my old plug from cyl. 4 looks like this.

One other thing i noticed spark plugs tips on driver side of engine were somewhat dry and orange and on passenger side of engine are wet black what does it signify?

 

The gaps on the plugs that were replaced appear to be pretty worn.
Black color on plugs usually indicates that bank is running rich, could be sluggish oxygen sensor, weak coil spark, too much EGR getting in there preventing complete burning of the mixture, rare, but not impossible to have faulty injectors on that bank. There could be other reasons too, can't name them all.

 

I got new PCV valve as i found oil in coolant maybe this will fix it a little bit, however its mew PCV valve is leaking little bit of air when i blow in it, isn't it supposed to seal completely?

 

Anytime we have an oil in coolant situation ,it warrants looking more deeply into why this is taking place. There cold be several reasons for this none of which are good to ignore. If the oil is getting into the engine coolant (oil pressure +or - 20 -50 lbs) (coolant pressure only 15 lbs) when the engine is shut down the reverse can happen and coolant might be getting into the oil. The #4 cyl may be responding to a problem in that area and things like this rarely ,if ever ,get better,but just get worse.
I wouldn't wait too long to get this checked out .

 

I am adding about half gallon (distilled water) per hour drive or so. Also i see oil in the coolant (water) i have suspicion its transmission fluid because now my transmission went from full level to low in about 1000 miles. I could change radiator its just $110 bucks for new aftermarket one.


Is there some test i can do to make sure radiator failed?

P.S. tranny fluid odd greenish/yelowish color.

P.P.S. Engine oil is at constant full level.