I'm leaning towards my valve seals since I'm getting blueish smoke at idle (hard to see while driving), and the good ole black ring on the hand when putting your hand to the exhaust pipe and it smells like oil.

I agree with the seals.

The timing, I'm not familiar with your engine. If it is geared, with a chain, GM probably used composite materials on the cam gear. (AKA, Plastic)

If that is the case, and it has jumped time, you are limited at how far you can go before it goes Bye Bye. It will strand you, and possibly bend valves.

Not sure if it is a non-interference engine.

Should be non interference, IIRC.

where'd you get three from?

TOC Admin
Brando

"My friend" and "probably" are not much help. As a matter of fact, just the opposite. Your friend's "diagnosis" caused everyone to focus on "the timing", instead of looking at all the possibilities.

Not your fault. The members, who replied, should have read what was there.


Yup. Then dink with it.


Is that when the backfire started?


Could be one (or more) of many causes.


Does a "good chance" make it so? Mmmmm, seems like I read that question on ROP recently.


How do you know? Did your "friend tell you?


Probably?


Could be?


Not the cause of your backfire.


Nothing that points to valve guides/seals.


Do we have any evidence that it is, or has?

Do we have anything, other than his, and his friend's, guesses at the solution? Do we have any symptoms we can actually work with?

Shall we start with this post from two weeks ago?

How many miles is that?

First, do a proper compression test. Follow the instructions given in your new Haynes Manual.

Norm

started after I replaced my battery, well the back firing, the smoke started before. 1KM is 5/8 of a mile. I'm ot the greatest with engines so I have to rely on others to help me.

Was that before, or after, you changed the plugs/wires?


So, can we assume it is not part of the backfiring problem?


It was a simple question. How many miles are on the car?


In order to get that help, you will need to read and understand what we post, answer all questions to the best of your ability, and follow the instructions you are given.

If at any time, you need clarification, just ask for it.



Then search for any loose vacuum hoses.

Norm

156250 miles, I changed the battery after the spark plugs and wires, when the spark plugs came out the first one (for cylinder 1) was black and burned out, also the last time I got my oil changed they overfilled it. The oil is gettign changed on saturday, also replacing the fuel filter as that NEEDS to be done and possibly the EGR Valve depending on how its doing. I can understand what you guys are saying at least so far, but for engine noises to what problem it may be I'm still working on.

It looks like you know more about your problem than I do.

Good luck with it. I am done here, also.

Norm

EGR Valve needs replacing but thats not too expensive and easy to replace. So that should help somewhat and with the new high mileage oil and oil filter. So after I get the oil change and shampoo my engine (yes I know how to do that properly) I'll give you gives an update on how my car is doing. Well from before I changed my battery and after my spark plugs were changed my gas mileage was horrific, but now with the new battery it seems to be somewhat better. I'm also possibly thinking about getting a new fuel injector if my gas mileage doesn't get better, in 2K4 it wa cleaned by a mechanic and I cleaned it recently myself so I think its time for a new one.

going back to the compression test, my dad's friend who has been a GM mechanic says my compression is quite good for the car's age and mileage. But I may have one done anyways. Also the high mileage oil is doing quite nice, the new fuel filter is doing well and the new EGR Valve is also doing a great job. So now just need to fill my tank up with gas to see how well things really are. Also an acquaintance of mine told me to try pure 100% acetone in my gas only about 3oz per 60L tank (15Gallons) which he said should help with gas mileage and some performance but I'm mainly looking for gas mileage increase since well the less I have to spend on gas the more money I can use for more useful things. http://pesn.com/2005/03/17/6900069_Acetone/ there is a link so you guys can read up on it.

I think I'm going to try it, if I notice little, no or a worse difference then I won't use it.

So, are you saying, it is no longer backfiring?

so far I haven't noticed any back firing, sputtering or anything like that, the back firing was intermittent but its damn cold here so I do expect some problems to occur but so far nothing out of the ordinary or expected. But time will tell if it helps with my gas mileage problem or how much help it will help with. After this tank either I will get the fuel pump (I need a new sending unit...thank you GM for crap sending units that never tell me the right amount in my tank) and other things related to the fuel system checked and if necessary replace whatever needs it. And after that I will try the Acetone stuff, I think I may try 1oz first tank, see how it does, and if I like what I see and hear then next tank 2oz and so on until I find the right amount.