YACT: Possible rod knocking

[Chaotic42]

I have a five speed manual 1995 Mazda 626 with an inline four engine and all of the sudden when I'm heading home from work, the car starts getting really jerky. I thought that I might have a flat tire, so I got out and checked and it's okay. As soon as I stepped out of the car, I smelled gas.

So I play around with it, trying to rev the engine up a bit, and it seems to get smoother as the RPMs increase, and it's much worse at lower RPMs. At idle (Around 700RPM), it's jerky as hell. I can feel it in the pedals, especially the brake, and also in the shifter.

I just had an oil change the other day.

There is a tapping sound, but I can't really hear where it's coming from. I'd say it's about five times per second at idle.

Any thoughts?

 

[canadageek]

no idea.....my car would jerk like hell any time i got near 3k RPM...turned out i didn't have a functional alternator all the time, and was running out of juice

 

[Colt45]

the tapping is probably just a lifter.

 

[Chaotic42]

Originally posted by: Colt45
the tapping is probably just a lifter.

How serious is that? Is it something that I need to get fixed immediately? I work nights, so if I need to get work done at the Space Center's garage, I'm going to have to move on to day shift for a day to let them work on it.

 

[RedArmy]

It could also be valve lash.

.02 cents

Edit: That would only be for the sound, for the actual reason the car might be acting up, it could be a billion things, if you say you smelled gas I'm thinkin fuel system or something around the intake manifold relating to the vacuum. Still, it could be a bunch of other things though, really hard to troubleshoot when the car isn't in front of you

 

[Cdubneeddeal]

Lifters are usually caused by wrong viscosity of oil or low on oil. If you had a rod knock, you would know it.

In the pedals, brake, and shifter you're describing..is that suspension you're feeling or engine compression?

 

[Chaotic42]

Originally posted by: Cdubneeddeal
Lifters are usually caused by wrong viscosity of oil or low on oil. If you had a rod knock, you would know it.

In the pedals, brake, and shifter you're describing..is that suspension you're feeling or engine compression?

I think it's the engine. It's directly related to the noise.

 

[Chaotic42]

Afternoon bump

 

[Chaotic42]

I'm convinced it's the spark plug now. It just seems like one of them isn't firing.