Originally Posted by engin_ear

Already told you what is probably wrong. It is serious. They should be able to fix it completely, if you DONT STRESS THE ENGINE IN THE MEANTIME. DRIVE IT SLOWLY SLOWLY SLOWLY BACK TO THE MECHANIC. DO NOT ACCELERATE QUICKLY, YOU CAN DO SERIOUS DAMAGE TO YOUR ENGINE. The sound you are hearing is "KNOCKING". It happens when the spark plugs are not firing at the correct times. This is also why you have no power. Spare me the explanation. GET YOUR CAR DIRECTLY BACK TO THE MECHANIC. DO NOT GO ANYWHERE ELSE. DO NOT GO TO WAWA FOR BREAD. Once they set the engine up properly again, you should be good to go. If they can't fix it, get it (slowly) to a Lexus dealer, then send them the bill.

Originally Posted by ClaudiG

NO it was NOT a Lexus dealer.....

I'm a woman - I trusted that it was rotten if they said so. I've been going to them for years - HOWEVER I'm totally annoyed and called them 3 times to tell him. I will go back tomorrow or Saturday.

I just drove home from work - only 2 miles....still not right. (I guess I thought maybe it was all in my head) NOT

So when I sat idle in the driveway I saw how the rpm's were jumping, slightly. Then I hit the gas to rev it and as I hit 5000 it sounded like something was going on under the hood. Hell if I know what - maybe the spark plugs misfiring? On the sidestreets I would gun it and I didn't like that the pick up wasn't quick enough and it levels off at 40mph. What is up with that?

I need someone else to hear and look at the car to see what they think.

Originally Posted by GSV8

Engin ear is right on. When the timing belt is put back on, there is a specifice location for the timing gear, which hence controls the timing. If your timing is off, the car runs like crap, sounds like crap and is just plain bad for the engine. One more time like was stated
drive slow
no revving
bringing it right back to them
heck tell them "My timing belt was not put back on properly, my timing is off. This should have been very evident to whomever test drove the car after the work was performed, if it was even test driven at all"

Good luck and lesson learned~

Originally Posted by engin_ear

Already told you what is probably wrong. It is serious. They should be able to fix it completely, if you DONT STRESS THE ENGINE IN THE MEANTIME. DRIVE IT SLOWLY SLOWLY SLOWLY BACK TO THE MECHANIC. DO NOT ACCELERATE QUICKLY, YOU CAN DO SERIOUS DAMAGE TO YOUR ENGINE. The sound you are hearing is "KNOCKING". It happens when the spark plugs are not firing at the correct times. This is also why you have no power. Spare me the explanation. GET YOUR CAR DIRECTLY BACK TO THE MECHANIC. DO NOT GO ANYWHERE ELSE. DO NOT GO TO WAWA FOR BREAD. Once they set the engine up properly again, you should be good to go. If they can't fix it, get it (slowly) to a Lexus dealer, then send them the bill.

Originally Posted by engin_ear

Apparently the timing belt is not on correctly, probably didn't get top dead center right. Your engine is fighting itself. Your timing is off. It's probably knocking, that's the noise you hear as the plugs fire at the wrong times. Power output will be way down for a couple of reasons.
This service should always be done at a Lexus dealer.
I doubt that you'd get any more pep from putting a new timing belt in. Car may run a bit smoother, but new timing belt is really more insurance from it aging and breaking.
Dirive your car very easily back to the mechanic, or a Lexus dealer. Do not accelerate hard. Probably easily fixable, if you don't break anything on the way back, and your mechanic can figure out what he's doing.
This would NEVER happen at a Lexus dealer. They would never give you your car back in that condition. Total embarassment. You paid HOW much for the service?

Originally Posted by Lex*Toy

Engin_ear is right. Check for timing belt TDC. Be careful like he said, or you will be in for serious... serious engine rebuilding.

If you had the means, I would have recommended towing.

Good luck.