what is wrong with my car?

[realracersuseapc]

ok my car is running reall bad right now. here is some things thats its doin:

1. when i took it out for a spin around the block i noticed a wierd sound comin from the engine. it sounds like metal hitting metal.

2. im getting really bad gas mileage.

3. i can definitely smell gas comin from the exhaust.

4. the idle will sometimes drop like 200-300 rpms and the whole car will kinda shake.


so heres what i concluded so far. its running rich, but the sensors should all be working, since the engine check light doesnt come on. and that metal hitting metal sound, could mean a messed up piston ring right? my friend told me it could be the timing thats makin the noise. like the valve or iginition timing or something like that.

can someone please help me diagnose my car? the mechanic wants $65 just to tell me the problems.

[AKADriver]

The sound could be knock (detonation). I'm gonna bet you've got a severely leaky injector. One cylinder running super lean, knocking, throwing off the O2 reading so the computer cranks up the fuel delivery making the other three rich.

With the engine running check for fuel ****ing out around the injectors.

[realracersuseapc]

i just replaced the injectors, so i dont think thats it. i also just checked to see if one was leaking and they wern't. what does knock sound like? i always thought it was kinda like a pinging sound. well the sound from my engine is more of a clanking sound. you cant really hear it until around 3k rpms. from then on its pretty loud. i really hope its not a piston ring, but thats what im leaning towards right now. im not an expert on cars though so any input on this would really help.

[uiuc240]

Originally posted by realracersuseapc
i just replaced the injectors, so i dont think thats it. i also just checked to see if one was leaking and they wern't. what does knock sound like? i always thought it was kinda like a pinging sound. well the sound from my engine is more of a clanking sound. you cant really hear it until around 3k rpms. from then on its pretty loud. i really hope its not a piston ring, but thats what im leaning towards right now. im not an expert on cars though so any input on this would really help.

Checked oil lately? Sounds to me like rod knock :eek: If that's it, you've got big problems, sonny.

Eric

[realracersuseapc]

rod knock? if it is, the only way to tell is to open up the engine and check right? and the oil and stuff is all fine. i just had a tune up done like a week ago.

[916s13]

if u have over 60,000 miles you should go ahead and replace your o2 sensor, i believe nissan says to replace them about every 30,000 miles. also when you just turn on your car you should feel the top of your valve cover right above the timing chain. if you can feel a ticking through the valve cover then it is prolly your upper timing chain guide. they don't even make them anymore for 96 and older 240's they say they are not needed and can just be removed. good luck with your car