radar737

I've got a '94 truck with 22re engine and 152K miles. Engine generally runs good and smooth, no smoking. But when I'm driving there is a knocking/tapping noise coming from the enigne with only very light throttle application. When your accelerating its fine and with your foot off the accelerator/coasting its fine, you only hear it when you give a light throttle input. Any thoughts would be great! Thanks in advance!

kyle_22r

sounds like valves might be out of whack.

ttr125mar

This same thing happen to me, I forgot to put the fuel filter back on after a put a new one in, it would hit the inner frame with a very loud knocking noise. It would only do it when I gave it gas (idle was fine). Check to see if any fittings are loose first before you start looking into big problems.

Thanks,
Mario

Bigblock

is it a tick or a knock?

radar737

It's more of a knock than a tap. I'm afraid it might be a rod bearing, but I hoped someone might have seen something similar. I'm also wondering if any type of timing chain problem could cause this noise.

PirateFins

If it is around the 2K rpm range then I would say timming chain. But that sounds more like a rattle, like running a stick along a chain link fence type sound.

GTE4runner

I had a rod knock that gave the same symptoms. It could only be heard at very light throttle at first, and it sounded more like a wrist pin than a rod knock. If you can get it to make the noise without driving it, have someone run the throttle while you crawl underneath it. If it's a rod knock it'll be way way louder when your head is close to the oil pan.