I bought a 94 camaro with a 3.4 for a few hundred bucks that somebody couldn't get to run.
Turns out they left out the oil pressure switch and plugged the hole so there was no voltage to the pump after startup.
20 bucks later it fires up and runs but i am tracing down the infamous 24x signal bug.
I've gone through all the flow charts I can find and every test comes back as a bad 24x sensor.
With a Tech2 installed I see no reference from the 24x signal or cam sensor. so both are getting replaced this afternoon.

It has a light misfire that steadys out about 1500 to 2000 rpm and gets worse from 2000 rpm up.

New plugs, wires etc. Plugs vary a little in color but one has me puzzled.
The number 5 plug has a black spot on the plug on the top side.
Not shiny or wet like oil, but black and sooty looking.
The car runs fine in town going easy but when you get into overdrive and load the motor hard the miss get quite a bit worse.

I am looking at pulling the injectors, which will be a chore.
Any other ideas on what would cause a black sooty spot on the plug. It's not wet though like a hung injector.

I will probably do a compression check tonight also if the miss continues after the new sensors are installed.
Money is dwindling quickly so I need to get it squared away before too long.
All help is appreciated so if you have any ideas let me know.
I'm getting very tempted to drop a carbed SB in there and call it good.
Thanks all

 

if the new cam sensor doesnt do it i would look at the coil or the injector.

 

I replaced the coil that controls that plug already also. also dropped 90 bucks on an ignition module too.
Just find it odd that it has a black spot on the plug.

 

try replacing the plug yet? sometimes even the new ones are no good.

 

Swapped the plug from the original to the new ones. Then swapped another plug to that cylinder and same thing.
24x sensor and cam sensor replaced and the idle is a lot cleaner up to 3000 rpm roughly..
Going to check fuel pressure in the morning. Would a knock sensor cause this on a camaro?
My s10 had a knock sensor go bad and it wouldn't give a ses light just made the timing go retarded. But it didn't miss.

Its not acting like a dead cylinder anymore.

 

if you unplug the knock sensor it should effect the way the motor runs if it doesnt then something is not right. if you have a bad injector or injector seal it will cause issues. we have had a few v6s here lately that have had the seals for the injectors fail. got brittle.

 

Haven't thought about the brings. But that could explain the glassy smell inside the vents and the horrible mileage. I am about to check fuel pressure and if it checks out my next step was to pull the fuel rail.

 

Ok. Haven't found the fuel smell yet. But no leaks at the injectors. and fuel pressure is spot on.
Misted water in the throttlebody at idle like we used to do for carbon build up in old trucks and it spark knocked once and even out. Runs like a top now.