mjtl

Hello. I just bought my first car, a 1996 TL 2.5 with 91,000 miles. I bought it from the first owner who meticulously maintained it and just gave it a 90,000 mile maintanance (belts,oil,transmission flush,water pump). As far as I know the car is in excellent condition mechanically. I just took a 300 mile trip from Los Angeles to Santa Barbara. Going there had no problems. Coming back is when the problem started. There was heavy traffic so I was constantly braking. After about 20 minutes of braking I heard a kind of knocking noise from under my feet. It wasn't loud but it was noticeable. And it seemed to happen every other time I braked. When traffic cleared I stopped hearing it. The next day I drove about 15 miles and it started happening again when I braked. It doesn't happen every time I brake but sometimes. I don't know what it could be. If it helps it happens when the AC is on and even when it is off. Also I didn't know I had to put premium gas in it. For about a week I put regular and mid grade. The engine seems to be doing okay. Not sure if it is related but I thought I should throw it out there. Has this happened to anyone else? Please I am very worried as I have spent all my money buying this car.

KaMLuNg

iTrader: (5)

what kind of knock is it? do you get shaking in your steering wheel too? does the pedal vibrate/pulse? we need some more info here.