I just bought a 94 Camaro 3.4 ltr 5 spd. manual from a friend of mine. He doesn't know much about cars andjust figured he'd buy a new car instead of fixing this one. Anyway, it idles rough and runs just as bad. I'm getting a vapor from the exhaust but it smells like unburnt fuel. No leaks on the motor. The check engine light comes on every now and then acording to my friend. I've never seen it on my self, but I've only cranked the car a handful of times.
I think it may be one of he coil packs that's gone bad because the engine has a steady miss and it just had a tune up right before my friend decided to sell it. Yes, it was running bad before the tune up... same thing, I'm told. I got it for $500 bucks and figured if I could keep repair costs as minimal as possible, I could resell for a little more money. I'm capable enough to work on it, but thought I would get some advice from someone who may have had a similar problem. Just have really bad ADHD so I have trouble reading thru all of the posts.
Any and all help would be really great! Thanks!

 

you might want to replace the spark plugs and wires that may be a reason for the miss.

 

SES light could be O2 sensor, but the gas smell could be the cat converter so I would smell around with the car running for a few minutes and see if that is where the smell is coming from (right under the passanger door).

 

After talking with the friend I bought the car from again, I'm pretty convinced the mechanic he took the car to was a crooked SOB. He said he had the plugs and wires changed and the cat converter replaced. I will say that the cat looks like it was replaced but the wires were cleaned with something to make them look newer and all of the spark plugs were rusted and fouled (rust around the hex collar, not the firing end.) On top of that, even if they were changed, they weren't gapped correctly. I think they were just old and fouled, though. Still, plugs with less than 500 miles shouldn't look that bad.
After a quick inspection, I replaced the plugs, wires, pcv valve, fuel filter, changed the oil and flushed the coolant system. The car idles like a champ now but has a steady knock. I'm hoping this just has to do with the fact that my friend was cheap and never put anything but 87 octane fuel in the car. I've put seafoam in the the fuel tank and the oil (as directed on the bottle), but haven't been able really run the full gauntlet of the fuel system cleaning yet. i.e., vacuum lines and intake cleaning. The other thing I'm thinking it may be is an exhaust manifold leak. I'm getting an exhaust smell and a little smoke under the hood on the driver side. When you give the car gas, it also sounds less like a knock and more like a pop.
On to the next problem. The car goes thru a really bad vibration right around 25-30 mph and it feels likek it's going to shake apart. I'm thinking motor mount or more likely a bad universal joint. I hope it's not all just wishful thinking, but I think I can get this hunk of junk back on the road fairly inexpensively... knock on wood!
Any advice or ideas what some of this stuff could be if what I'm trying doesn't work?

 

I had the exact same problem, went and got the codes read... bad coil pack.. Get those that fixed and you wont have any problems... (you said you changed the plug wires right?). Or just go to the shop and get them to read the codes... but I am 98% sure that if you fix the coil pack you wont have a problem.. The coil pack is causing misfires and that is the most likely root of your problem. You need to get this fixed fairly fast tho, the longer you sit on this problem, the more damaged you car will get.

 

I'm still having the problem. I have no idea what could be wrong... I'm still getting what I would call a dead skip and a gas smell at that tailpipe. I'm baffled. It has an exhaust leak on the front cylinder on the driver's side that's pretty loud and it kinda makes a tick noise along with the papery sound that comes with an exhaust leak.
Could it be injectors?!? I'm out of ideas.

 

Injectors do tick and can be misconstrued as a knock....... When i replaced my 3.4 suddenly i had a tapping sound. put a hose to my ear and listened and sure enough thats where it was coming from. Have you checked for discoloration (rust) on the ends of the coil packs (where the wire attaches). That dead miss may be caused by corrosion build up.... If so use a little emrey cloth and polish it right up... also if you use a dielectric it will help prevent future corrosion. You have to remember you are dealing with DIS which equates to High Tension......... just a small amount of resistance equalls a massive loss of power.

 

Scan thePCM & see what is misfiring. A bad coil will show 2 bad cylinders, the ignition module under the coils will show multiple misfires. Bad injector will show as single cylinder misfire.