Cavalier problem 2.2 engine 134,000 miles after engine is warm knocking noise coming from head 1994 year cavalier

2az-fe right?
no mileage stated,, is he cam chain making noise, ignored?
get it serviced?
or buy the tools and do the tests DIY.
which choice? only 2.

• 2000 - 2.4 L (2362 cc) 2AZ

smoke is a bad sign, on low mileage engines say below 250,000 miles and with noise worst. there must be no noise, on this engine.
no HLA's to rattle there. has solid bucket tappets.
then mean they never make noise unless, its damaged or lacking oil.
are you doing silly SYN oil changes it 25,000 miles or at 5 to 7k miles.?
id do a cylinder leak down test. by hand to protect engine from
further damage, (I do that on all DOHC engines (savvy i am)

From your description of the knocking, mileage, and oil crusted on the intake valves you need an engine or a complete rebuild of the original.

blew something in lower end --oil pump damaged --no oil or low level --check oil pressure then do compression test as well --since knocking noise is usually called rod knock

Hello
Any knocking noise is more than likely due to worn connecting rod bearings, Crankshaft main bearings or piston or piston pin noise. Connecting rod bearing knocks and piston related noise quite some with warm up, piston noise tends to go completely away after about 5 minutes of run time, but there are exceptions to that run like a cracked piston skirt, crankshaft bearings don't quite very much. It would be my best quests without hearing the noise that you may have either a connecting rod or piston related noise. The best thing to do here is have a trained ear listen to the noise, any experienced technician will know very quickly what the noise is and where it is coming from. These types of noises are only common on high miles engines, with at least 100,000 miles on them is the general run or the engine has been run very low on oil repeated times, or the oil not changed at regular intervals or the engine has been severely overheated. My experience? 35 years as a dealer technican. I'm Master certified in all phases of auto and light truck repair.

Hard to say over the internet but I will try to explain. If the noise is a distict KNOCK KNOCK and it sounds like it is coming from the bottom of the engine, then it most likely is a rod or main bearing. If it is a TAP TAP noise that sounds like it's coming from the top of the engine, then most likely a valve lifer is failing/failed.
the fact that it goes away when the car is warm, makes me lean towards a bad lifter. Normaly if a bearing is bad and knocking, the noise doesn't go away.

The KNOCK noise will be somewhat hollow sounding and the TAP TAP sound will be more solid. If the KNOCK KNOCK is solid, then a rod or main bearing has most likely failed to the point that a new/reman engine will be needed.

No if the oil light has flickered you have oil pressure loss some time just belive the sensor do help us out. lifter do not cause oil pressure loss pressure is built in the rotation of the crankshaft. The knock under the plenum will point you to that cylinder that is affected, (main bearing) as for a 1995 the injectors can only cause a misfire but no knocking noise,will they honor the warranty

Check for an exhaust leak at the exhaust manifolds and flanges.

Just start it up, check the oil and water for white sludge, a sign of head gasket failure. and just listen to the engine for rattles and knocks and bangs. also look at the colur of the exhaust gasses, after it has warmed up. A small amount of water dripping from the exhaust is normal for cars with catalytic converters, but dark blue/grey smoke is a sign of wear in the piston rings. An engine with 195,000 miles on it is not necessarily a problem if maintained and serviced correctly before and after.

I think the engine is most likely defective, the used one is the best bet, try and find one with low miles, you can do a nation wide search here.
http://www.everdrive.com/?gclid=CLvWheWo55kCFQ9JagodE3OySQ

There could the short in the wiring which is causing the sensor to malfunction on the car check the sensor if they are good in the car...