JayKay

90 psi approx. on 1 & 2 60 psi approx. on 3 & 4 Starts and idles a little rough with no load but as soon as you put it in Drive it runs very uneven and has low power. When you try to accelerate, there’s a loud “clatter” from the engine. Hard to describe a sound but light, not rod bearings. Almost like detonation although I don’t think it is detonation. New coil packs and plugs on all 4 cylinders. Injectors cleaned and tested. Borescope on 3 & 4 looks OK but you can’t see much , pistons look reasonably clean and not damaged. Could be the head gasket has failed between the two cylinders? No sign of oil or coolant contamination. Also, I don’t think that would explain the noise. Could it be the valve gear? I’m not familiar with these engines with variable valve timing. Is it possible something’s wrong with the valve gear, possibly the valve timing? Any help to diagnose this problem is much appreciated. JayKay aka John Kenneth

😊 Thank you

Thank you, very good advice. the sound is "hollow" to try and describe it and sounds and feels as if it has something to do with the servo/booster diaphragm. I can't get to it for a few days but will report back with results.

2007 Avalon 132K Recently purchased. Brakes work fine but pedal has a little resistance when first pressed and "creaking" noise when pressing or releasing brake pedal. Seems to be coming from white plastic cylinder (see photo - with rubber bellows pushed back ) This cylinder is lubricated and does not seem to be binding. Noise seems to be coming from booster on the other side of the firewall but booster seems to work fine. Previous owner said he had recently changed the master cylinder. Anyone else encountered this problem? And any ideas how to fix it? Thanks, all help is much appreciated. John Kenneth

Just purchased an Avalon and also find myself working on other family Toyotas specifically a Corolla and Camry. This looks like a great forum and I look forward to contributing and receiving here. JayKay also known as John Kenneth