miss on 94

[94conv.]

Guys, I think I may have blew a muffler the other night, pop, then some funny exhaust coming from the left side, but just for about a minute or less, then everything seemed fine. Took it out today and it started out fine then on the way back from about a twenty minute ride it started to want to miss when I kicked it down and the exhaust sound was back, a little louder and real gravelly sounding. Does this sounds like a optispark condition or could it be a bad muffler? I was going to replace the mufflers after the first incident but decided to wait it out and see if it was just a fluke and a one time occurance but this time it was bad and definately effected diveability. It didnt set any codes.
Thanks for any replies.

 

[redc4corvette]

Mine bubbles but I think that is a normal noise for the Lt1 and ls1.

 

[jmccloud]

Muffler noise

You may have a cracked catylic converter. If the honeycomb fractures and starts rattling around, it makes some strange noises. It may have to warm up to loosen up. I had a Buick once that did that. Every trip was a new sound. Eventually a piece of the honeycomb turned sideways and caused a severe exhaust restriction with resulting poor high rpm performance, poor vacuum, wierd ventillation air discharge, and loss of cruise control.

 

[94conv.]

I drove it again last night and everything was alright but I didnt go as far so the temps may not have gotten high enough to mess with the converters, it was a distinct miss while idleing the when it happened this last time. Last spring I had a mishap with the optispark collecting moisture and it wouldnt run at all, missed out and backfired, took it to the dealership and they sprayed some drying agent in it and it worked alright after that, this is why my first thought is/ was the optspark. I havent noticed the waterpump leaking or whining or any signs other then the smell of radiator fluid briefly while driving, I havent looked into this smell other then it seems the smell comes in right when the temp is going up then it goes away, almost like the thermastat opens then the smell goes away but I havent tested this theory. I would like to narrow it down before I drop the cash for parts, a couple of weeks ago when I thought I blew a muffler, I was ready to go out and get a new pair, now Im at a loss on what it is. I was leaning towards optispark but the converter could be suspect.
Thanks for the replies so far.

 

[jmccloud]

Miss

Do searches on optispark and water pump.
If you smell antifreeze, the water pump is probably leaking out the 'weep hole' onto the optispark. Use a dental mirror to look under the water pump after a cold start and enough running that corresponds to when you usually smell coolant. If there's liquid coming out of the weep hole on the bottom side of the water pump, don't run it until the pump is replaced.
Drain completely (remove the knock sensors in the lower center of each side of the block as well as draining the radiator) before pulling the water pump off. Still, place a big towel between the water pump and the opti to keep the opti dry.
Search regarding bleeding (letting all of the air out and cycling at least 3 times from cold to warm).
Good luck, doesn't sound too bad.

 

[My Prozac]

I hate to say it but that sounds like and opti spark problem mine did the same thing after I got it wet by cleaning the motor and finished it off, I thought I did all the damage by getting it wet but once I took it to the garage I found the water pump had been leaking, it sounds like yours did the same thing.

 

[94conv.]

Thanks guys, Im looking into the dynaspark made by dyna-tech engineering, http://www.dynotech-eng.com/dynaspark.htm .Its a billet alluminum piece and has the vacuum lines on it, I suppose like the 95-96. Its $599.00 though, do you guys think its worth the extra? Also is there a better water pump then what you can go to autozone and get? I would probably get a GM water pump before I go to Autozone, that place is ok for parts for my 96' pickup but I dont know if I'll go there for the vette. Thanks for the info.