Mechanics

CONSTENT LOUD BANG AT IDLE

1998 Pontiac Firebird

Engine Mechanical problem
1998 Pontiac Firebird V8 Two Wheel Drive Automatic 166000 miles

first off, my car is a trans am. 5.7 liter fuel injected, no distributer but ignition coils. I turned my car on yesterday, I noticed a hesitation, and a loud noise like something hitting something. It only does this when it's in drive and I pressing on the brake. Once I start moving the problem goes away(hesitate on take off). My cars been having an Idle problem, rpm should be around 1000, but go down to 600. But the sound is bad(bang, bang, bang). I did some checking and notice that there was oil in the spark plug holes, which I thing is responsible for the low idle. any help on situation will be appreciated. thank you. ( is my piston hitting the block because valve are not working correctly


http://www.2carpros.com/forum/automotive_pictures/133498_engine_1.jpg

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Tyrantxzero
March 24, 2008.



Id start by checking the torque converter bolts and while in there, look at the flexplate (flywheel) to see if it has any cracks in it, use a bright flashlight and look close

Tiny
Jack42
Mar 25, 2008.
I have notice some weird noise when it shifts, and when I put car into drive. I also notice a little oil leak near the end of the transmission near the driveshaft. I will check that today after work. Thanks

Tiny
Tyrantxzero
Mar 25, 2008.
I have a 98 Trans Am, its 5.7 liter automatic. The problem I am having is weird noise when idle. Idle low (500 rpm, it suppose to be around 1000), loss of power, and when at full stop it hesitate when running again. I started having this problem about a week ago, but the low Idle; since I bought the car (about a year ago). At first the idle wasn’t that bad it would shake a little (low compression maybe, because my car would sound quite at a stop light). It only did that in drive, it would not have this problem in reverse nor neutral. Also when I start the car it turns on weird (it idle high for a bout 30 second (1400 rpm), then they go super low (500) and back to around 900 rpm, also happen when I shift into drive or reverse. I wanted to fix the problem before it gets worse. First I removed the throttle body and there was a lot of carbons build up. Cleaned but nothing, problem remained. Second I changed the idle air control valve, new MAF sensor, and speed sensor, but nothing. Third I gave it a tune-up, changed the oil, sparkplugs (iridium), and wires. When in the process of doing this, I notice oil in the spark plug chamber (a lot). I think that is why I am getting the low Idle. I know that it could be one of 2 things, the piston rings could be bad or the valve path is leaking oil because of bad seals.(How can I tell?). A month later I stated hearing this noise (bang, bang, like if something is hitting); this only happen in drive, but now even when in park. I just don’t know what to do. I don’t want to take it to a mechanic because where I live(Laredo) no one knows what to do and I also get the run around(like it the fuel filter, I sure, I put a new one a week after I bought it) any help on this matter, would be great. Oh and it now making a clicking noise, I think it’s from a valve. My car is just messed up! Help!

Mods-EGR removed, block off plate. (Is the computer supposed to be programmed for this?
New headers and y-pipe- SLP
New exhaust muffler - Flowmasters
MAF - modification
Oil changed – put thicker oil because mechanic told me it would help (it didn’t) - 160,000miles, 5w30 to 10w30.
New spark plugs – Delco iridium and MSD wires,
New oil filter - K& N
New air filter - K& N
New thermostat - 160 degree
New Speed Sensor
I put some additive in the gas- NOS, etc
Oh and a throttle body bypass (for coolant)
And also fixed the secondary air system, the smog pump was broken(don’t know why, I don’t thing I need it)

I havent had time to check what you asked me but will get to it this week. Thanks

Tiny
Tyrantxzero
Mar 31, 2008.