Marc3.4V6

iTrader: (1)

When I accelerate a lot of the time I've been hearing a soft but noticeable sound that I'm told is knock and or ping. Just in case, I'll describe the sound as similar to a propeller engine airplane's engine turning off, kind of like ping pong ***** in a washing machine only quieter.

Whatever it may be, should I be worried? I always run premium, and usually get 76 station gas, though lately have been getting Valero gas, which is not a top tier gas if it matters. I'm pretty certain it didn't always do this, I've only noticed this within the last 1-2 months. It has actually been running uncharacteristically superb for quite some time now. Doesn't feel slow, plenty of power, but now I'm worried about this.

Motor has almost 30k on it.

LT1FirebirdSLP

iTrader: (2)

Your having detonation issues. This problem definitely needs to be addressed. Any codes? Could be an OPTI issue. Could be a bad knock sensor, since if the knock sensor is doing its job correctly, it will pull timing to counteract any knock/ping. Does it do it all the time... motor cold/hot? Going up hill worse than when on flat ground? You could try different gas but I suspect this is not the issue. What are the conditions of your plugs/wires? Pull a plug if you can and tell me what color it is, or take a pic. Your looking for all 8 plugs to be coffee/tan colored. Black means your running rich. White means your leaning out. Give us an update.

Marc3.4V6

iTrader: (1)

Thanks for the reply. I'll take a look at a plug this weekend. Plugs and opti have about 20k on them. It may be worth noting that I have a newer set of wires on one side as I haven't had time to do the other side yet, although this happened before the new wires, it seems to be happening more often now. The passenger side wires have 20k on them, the driver's side maybe 200 miles. I found the number 5 plug had been pretty badly burned past the insulation and had split into the wire, it was actually running good, so i had no idea. I put an LT4 knock module in the car when the motor was at 12k. It occurs as far as I have noticed in closed loop and does it 2-3 times per drive, but not usually on short drives. Although not always on a hill, the type of acceleration it occurs in is just like the amount of gas you would give if you were going up a hill. It seems also that it happens when you're coasting and you give it the gas, like coming out of a turn and accelerating when it gets straight. The car has also always backfired/misfired in a pop sound in the front occasionally and I've never been able to figure out why. I also smell coolant often when I turn off my car or sometimes at a stop light but have never been able to find it, so could be waterpump weephole onto opti. Though I do have a cowl hood so I naturally would smell stuff more, even though I smell it the strongest right as I'm getting out the car.

Marc3.4V6

iTrader: (1)

I should mention I've also had a sort of power speedbump at round 3700 rpm wher ehte power sometimes flattens but past that it's fine. Also I'm now getting smoke during acceleration, but I can't tell what color because it's usually on the freeway or I am just moving too fast.

jaycenk

iTrader: (1)

Do you have coolant leavel problems? If so could be a head gasket letting go. While you have the plugs out do a compression leak down test, check the coolant for carbon with a test kit, check the oil for coolant. A good tune up may be all it needs but coolant entering the cyclinders can cause some smoke (steam really) but the color isn't always white since it is steam it literaly steam cleans the piston, head, and exhaust system. And since you cant find the coolant smell try sniffing the exhaust and see if you smell coolant in it. I smeeled a hint of coolant in my exhaust for months before the head gasket let go enough to warrant me pulling the heads.

Marc3.4V6

iTrader: (1)

No coolant problems. I've got shorty headers, only way I'm taking out more than one plug is if I'm changing them all.

Today it missed in a way I've never heard before. It was very similar to the ratcheting sound you get when trying to start a dead battery.