burning oil

hopefully someone can help....I have a 96 rodeo with a 3.2 v6 and I'm worried that I am going to have to do some major repairs. As I was driving home today it started knocking and the check engine light began to blink. As I drove it the short distance home I noticed that the engine idle was erractic and it felt like it wanted to die at stop lights. After getting home I began to try and figure out the problem and had it idling....as it was idling the knocking stopped and it began to smoke...of coarse, it smells like burning oil. Don't think its the ERG and I'm leaning toward a problem with the pistons. If so, how hard-or expensive will this repair be. Any info would be very helpful. Thank you.

How old/mileage is on your timing belt? The knocking could be explained by the timing belt tensioner - sounds MUCH like a rod knocking when it's going bad.

If this is your original timing belt at 11yrs old, I'm almost certain this is your issue, and timing could be slipping, thus causing very erratic idle and other symptoms. However, no permanent damage would result.

New belt, timing belt tensioner, and waterpump and you'll be good to go.

If your timing belt is fairly new, however, <65K/4-5yrs, then I'm not positive.

But, also double check spark plugs, fuel/air filter's if needed as well.

Forgot to add: Burning oil smell could be your timing belt - it is rubber after all.

I'm not so sure that the timing belt would be the problem. I'm pretty sure that the timing belt was changed shortly before I bought it. Also, seems like there is too much smoke for it not to be oil. I'm not positive about a rodeo, but seems like if I threw the timing belt that the vehicle would no longer run. Before the knocking stopped it seemed the noise was coming from inside the valve covers....but it's always hard to tell exactly where engine noises are located. Also, when the knocking stopped the idle smoothed back out to a pretty steady rpm. Thanks for the reply...hopefully this will give a little more info.

Check the history to see if the timing belt TENSIONER was replaced with the new timing belt - if it was not replaced at the same time, it WILL fail shortly after a new belt is installed.

The timing belt tensioner IS the weakest part of the whole set-up, and if it gets weak, will cause the belt to stretch - but the truck will still run, it will sound like you're throwing a rod. Through my own experience, the truck WILL keep running until that belt actually comes through the timing belt covers, which are directly in front of the valve covers.

Mine never came through the valve covers, but golly, it sure sounded like a rod was about to be thrown from Colorado to Florida. The noise I was hearing was the belt slapping against the timing belt covers; if you raise the RPM's a bit, it will - sometimes, tighten the belt/tensioner back up, thus the idle smooth's back out.

Could be other things as well, but this was my experience.

If the timing belt AND the timing belt TENSIONER are BOTH new, then look elsewhere - only other thing I can think of, is pulling the spark plugs to see if oil is swimming inside the boots, and check very carefully around your valve cover gaskets, if you have a BIG oil leak, this could cause smoke with oil hitting your driving belts and/or exhaust.

How much oil are you going through in a week?

Keep us posted, I'm not really sure what else to suggest.