Toyota Corolla louder engine noise

[Legend Cox]

Slowly over the past 3 years the engine In my 2004 Toyota Corolla has gotten mechanically louder, and sounds a bit rough under acceleration, no codes. What could cause this? Has no vacuum leaks. New spark plugs, and clean filters.

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[Richard Kirshy]

Could be a broad range of causes:
Start with basic maintenance:
Correct spark plugs
Cap, rotor, wires
Clean the MAP / MAF sensor

Does it require timing belt maintenance?

You do not state how much mileage, could be engine wear.
You say “mechanically louder” …
Do you mean the valve train, engine knock, pinging…..

[Legend Cox]

Spark plugs are correct and gapped, it has a timing chain and electronic coil over plug ignition. 105000 miles, hydraulic lifters, and I do regular maintainable on it. MAF was cleaned 15000 miles ago. By a mechanical sound I meant it’s a bit like pinging but very light, like a hammering sound that you might expect from an old v8 at full throttle, but only on one cylendar. I did do a compression test a while back and the number 4 cylinder had only 70 psi wet but that may have been an error in my method of measurement. The rest were around 95-100. Previously I replaced the timing chain tensioner which was loose causing the chain to tap against the valve cover due to carbon in the oil passage. For the first 73000 miles it was driven mostly in town by my grandparents, causing a lot of the carbon buildup, but I have cleaned it out pretty good.

[Richard Kirshy]

I would do a proper compression test first.
The numbers you show are extremely low ..
From what little research I did ….
This is stated for a 2002 model year

Attachments:

• ManualComp2.jpg

[Legend Cox]

I’ll probably try this tomorrow, and report back with the results.

[Legend Cox]

It seems as though this engine just tends to run noisily as it gets wear on it, and compared with other people’s is normal.

[Author]

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