Very Loud Tapping Noise

Yesterday my car (1991 Celica GT - 2.2) began making a tapping sound in the engine. The more i drove the louder it got. It's louder and quicker at higher RPMs. Perfomance wise it drives but has some hesitation, sponginess..loss of power. It stalled once and took a while to get started back up. It sounds like the tapping noise is coming from one of the valves. Anybody here know what the deal is?

is it tapping or clanking

wounds like u have a bad valve, prob just needs to be re shimmed

or you could have rod nock, in that case your fucked

Yeah everyone has told me similar - bent valve, broken rod, etc

tkae a stethiscope, and listen to various parts of the engine while its running (not too hott it will burn the silicone tubes on the stethicope) if you hear it coming from the head, its a valve, from the bottem of the endging its somthign with the rod

an easyer way to find out is to do a comp test, if its a valve then the compression will be a little lower htan the other cylinders (assuming it was equal before) it wont be lower from rod nock

A compression test will only appear lower because of a valve when it is too tight, but since it is making a tapping sound then they must be loose, in which case the compression would stay the same. It sounds like you may just need to adjust your valves. When you do adjust them look for tight valves because as a rule of thumb, a tight valve makes the car run rough, and a loose valve wouldnt be noticable expect for the noise (most of the time). They can be way to loose but that is the rule of thumb with valve train diagnosis. You could have some tight causing it to run badly, and a few loose to make the noise. So the the first step you should do is take off your valve cover and take a feller gauge to your valves, not to adjust them but to see what they are at so you can either condem them as the problem or eliminate them as the problem. The specifications for valve clearence is under the hood.