Ok, here's the story......I had to change my valve cover gasket because of oil getting into and fouling out the spark plugs, after that, suddently my car doesn't want to start, bad battery, changed it too. Now I have black smoke and black gunk coming out of the tail pipe, it runs like crap and I keep getting the *engine too lean* code. I have been told by at least one place that it was both oxygen sensors, but I have also been told by another place that it wasn't. I definately don't want to make a $400 mistake. what are the easy (i.e. cheap) things I can repair or change to see if it is something other than the o2 sensors?

 

is the check engine light on????

 

Black smoke means you are burning oil big time. Did you put the gasket on correctly? Might want to take a look at your cat now also.

 

well, it's not billowing black smoke, and the black gunk comes out in little dabs. I had a mech go over the gasket and he said it was a-ok and there were no vaccum leaks.....I am wondering if the oil from the valve gasket got into the o2 sensor somehow and fouled it out. is that posible?
should I start by cleaning the maf and replacing the pvc valve or what?

 

I would check the PCV, but the neon doesn't have MAF sensor.

 

you put the valve cover on wrong. that is what is wrong. take it off and do it again. i had an avenger valve cover that didnt quite fit, and did the same stuff. it blew a huge cloud.

 

Update: I have changed the spark plug wires and the plugs (again) changed the air filter and even found a vaccum leak and fixed that. However, on start up it idles poorly like it is going to die unless you give it gas, and when the engine revs it blows out black gunk and soot from the tailpipe untill it is warm, when driving (which I do little of) I have to press the pedal to the floor to get it to go, but once it gets up to speed, it is alright.

Any suggestions?

 

IAC valve? If it is not letting enough air pass it will cause the motor to load up. It clears when you step on the gas because you are opening the throttle body and allowing more air to pass through the TB which brings the A/F ratio back towards stoich.

Black stuff and soot out the tailpipe can also be an indicator that the converter has gone south. With a bad converter your car will idle and run poorly at lower RPM, but when you get on it and get up to speed it will clear up because you are forcing the exhaust through it harder than at idle. Drive it about five miles at night at a good speed. Not speeding, but not in stop and go traffic either. After about five miles, stop the car and hop out and look under the car atthe converter. If it is glowing cherry red and shining like Rudolph's nose, this is a sure indication that the cat is bad. The reason it glows is that the carbon/soot is burning in the converter because it can't get through, and this generates a hell of alot of heat. (no pun intended) If it is not glowing, it does not mean it is not bad, it may not be bad enough to cause the blockage needed to create the heat needed to make it glow bright red. Remember, this is just a seat of the pants test and look see.

based on your thread and description of black junk and soot out the tailpipe, I would lean toward a bad cat. It seems that you have the ignition stuff covered.

 

ok, now for the part that will make me sound like an idiot....what's an IAC valve?

I will try the road test later and post the results....

 

Idle air control valve. Being an idiot would be for you to not ask! Smart man.