'98 Corolla engine knock

My '98 Corolla (1.8L) has piston knock noise when it is cold. It is totally related to temperature. On cold days it is fairly loud on acceleration and decreases as the car warms up. When at operating temperature, it is not noticeable. On warm days, the knock is not as loud and goes away quicker. I bought this car used, but all the receipts show good regular maintenance. The car had 42K miles on it when I bought it and the noise was evident then. I have 93K on the car now and the noise still goes away when warm and the car uses no oil.

I heard a car start in the parking lot the other day that looked to be the same year and model of my car. The piston knock came from that car also. Is this common to Corollas with this engine?

I maintain a fleet of about 40, 1996 thru 2003 Corollas, and they all have the cold weather knock. However, it usually only shows up when it's 35F or below.
The lowest mileage car out of the group has 101,000 on it. The highest has 250,000 miles. I have a 141,000 mile '96 GMC 4X4 pickup as my personal vehicle and it does the same as the Corollas if I don't let it warm up for a few minutes. It's done that since the 40,000 mile mark when I bought it.
Don't worry about it but I do suggest letting the car warm up for 5 minutes before you drive off. The knock should be gone by then.

Good luck!

Thanks for that information. It is good to know it is common and not a problem. Yes, I do let the car warm up for a few minutes and that seems to really help. I take it easy on the acceleration till it warms up also. Thanks for responding.