General Maintenance & Repairs - Random Misfiring, mechanic says its ok?

I'd like to start off by apologizing if any of this is obvious, I'm still new to F-Bodies and I don't have much car knowledge :emb: the car in question is a '96 Trans Am.
So I had taken the car to a mechanic, and put a lot of work into it to make it run right and pass smog. Since then, the check engine light came on again, for P0300 random misfires. I brought it back to the mechanic and he said that LT1 birds are prone to misfiring and its not a problem, I should just drive and enjoy the car and not worry about it. Can anyone shed some light on if this is bullshit or not? The car is virtually stock, T56

Bullshit. No car is "prone" to misfire. Check spark plugs wires clean MAF and Check the opti those are a few common causes of misfires.

What 14 k said! Bull bull bull. I am a technitian and I would never give that answer. He or she needs to be honest about the problem. Think about it: will your car pass inspection with a check engine light on? Would the manufacture be able to sell a car that polluted? Missfire is the worst thing. It will ruin your cats. Maybe the problem is not the mechanics fault but the mechanic has to finish the job or tell you they can't. Sorry but that answer pissed me off.

That's what I thought, it sounded fucking stupid. What I don't get is by telling me its fine I'm avoiding paying him more, so I don't know why he'd tell me what he did unless he believed it...what got fixed before was oxygen sensors, ignition cap and rotor, spark plugs, ignition wires, and the fuel filter. He said just drive it about 100 more miles and i'll be good to go for smog, which i'm sure won't be the case...

They tell you it's fine usually when they don't know how to fix it.

Start at the easiest places. Pull the MAF out, and clean it with MAF cleaner from an autoparts store. Throw in a new fuel filter if the old one hasn't been replaced.

After that, I'd check out the coil, located on the driver's side head. It's easy to take out, and can be tested at any auto parts store, to replace one it's about $40 or so, so pretty cheap.

Next, see if you can see any obvious breaks, tears, or burned spots on any of the spark plug wires. Replace them if neccessary.

After that, spark plugs. If they haven't been done recently, it'd probably be a good idea to change them anyway. ALL 8 of them ;)

If all else fails, it could be the opti-spark distributor. People love to bitch about these on LT1's, but truth be told they're acually very durable unless you get them wet, or expose them to excessive heat or really high revs (much higher than stock). They do fail sometimes, just like any part on any car, but it is labor intensive (not hard, just takes a while) to replace. Don't go blaming it right away though like many people do, because it could just be a simple, cheaper fix.

Alright, thanks a ton guys I'll try all that :) not sure why the mech couldn't do it himself but oh well, hopefully I find the problem without too much trouble

Do you know what brand o2 he used? I wouldn't use anything but Denso/Ac Delco sensors on these cars (or any car for that matter). Bosch o2's have given alot of people trouble and I bet that's what he used.

my Bosch work fine, why do people perpetuate BS rumors? but...........I would suggest you find a NEW mechanic.

my Bosch work fine, why do people perpetuate BS rumors? but...........I would suggest you find a NEW mechanic.

Your Bosch O2s are like my Cardone Opti. They work, but it's a once in a blue moon kinda thing.

my Bosch work fine, why do people perpetuate BS rumors? but...........I would suggest you find a NEW mechanic.

Haha, just because yours work fine doesn't mean other people haven't had issues. All you have to use is your search button and a little common sense and you'll see a bunch of people don't recommend them- people with alot more knowledge than you or me.

Your Bosch O2s are like my Cardone Opti. They work, but it's a once in a blue moon kinda thing.

See you guy's......they sell hundreds of thousands of these and a few people determine that they are the mass and bad mouth the product. I'm glad I have my knowledge and do not have to rely on others for MOST of my answers.

Regardless of which ones suck and which don't, I have no idea what brand he put in anyway. Urg...next time I'm gonna try to figure this crap out on my own instead of relying on a mechanic blindly...

My buddy has been through 4 or 5 Bosch o2's in 2 years, and about 10k miles just fyi lol. But usually bad o2's throw a seperate code so I bet it's not that.

Well, I cleaned the maf just before I went away for a week, didn't look to bad but hopefully that helped some, it'll get some long highway miles when I get back so I'll see how it does. Still gotta pass smog...