Q: After major engine work, car's response is slower. Having to push the pedal harder then usual. Seems like torque or power loss.

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My timing chain snaped while driving. Luckily i was only going 10mph but the damage was done. 4 valves were bent and damaged the cylinder head. Went to my local mechanic who replaced the valves brand new BUT he sent the head to a shop where I guess they refurbish it? Also he replaced water pump, chain, pullies, tensioner spark plugs etc. After a month, I received my car back and immediately noticed it doesn't respond the same. I put those chemicals in the gas tank where they clean the fuel injectors etc. It helped but didn't fix the problem. After confronting him about it, he prides himself saying he did the job very carefully and accurately. Could this be permanent power loss sense he re-used the same head? Do I have to get a new engine or is this recoverable? No engine codes are on when I checked for them. Lets say your accelerating and take your foot off the pedal and feel that jerk of deceleration. Thats the feeling I'm getting when first taking off without removing my any pressure

My car has 96350 miles.
My car has an automatic transmission.

I looked up your vehicle and it does not list a 1.8 l turbo engine for a Golf. It does for a GTI. This is a gas turbo engine. Replacing the head should not be that hard and as long as your timing belt was put on correctly so you should have equal to or more power. When I say more power, I mean that if the head was shaved or machined flat and they took off some of the surface, this would result in the compression increasing.

I would recommend that you should give your car a couple weeks for the computer to completely adjust. If after a couple weeks you still have reduced power, take it back to have him to ensure that the timing is correct on the timing belt and that everything is operating properly.

If you mechanic is unable to help you, try taking it to the dealer to have it diagnosed for the problem without telling them what was done. This way it will be a completely objective diagnosis to find the source of the problem. You will have to pay for the diagnosis but if something was installed wrong you’ll have information to relay back to the mechanic that first did the work for you if he did something wrong.

Before going to the dealer, try and run some high octane fuel to see if any performance is improved. You may have a weak turbo boost causing this problem, the dealer will check and let you know if this is the case. If you bent a valve and a piece or chunk of carbon bent or damaged the turbo then it will show as a low turbo boost.

If the problem isn’t fixed at this point, contact a certified mechanic who can diagnose your loss of power and make the necessary repairs to get your car running normally again.

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