This morning when I fired up the Monty she knocked 3 times as soon as she started - thunk thunk thunk - and then ran normally. This is by far the coolest morning of the year (50 degrees) so far, and I had similar noises last winter, so I I am pretty sure it is temperature dependent. What could cause this? Maybe piston slap? BTW, plenty of oil pressure and oil level is fine. Anyone else have this problem with this engine before?

What weight motor are you using (although, 50 degrees isn't that cold)?

10w30 - valvoline high mileage oil

After sitting for about 10 hours in the parking lot at my job it started with no odd noise this afternoon. Tomorrow morning @ 6:00 AM temp will be in the 60's outside and I bet it does it less or not at all. It isn't a high pitched ping like valve noise or really a harsh bang - more of a muted sounding thud. Very regular rythm too.

When it was seriously cold last winter it did a much longer time on cold starts. Since then I had had the timing belt done, new plugs, new dist cap, dizzy, and wires, and new t-stat. I thought maybe one of those had fixed the noise, but apparently it was just the warming weather.

I was thinking maybe I needed a better oil filter with a good anti-drainback valve, but wouldn't noise caused by lack of oil in the top of the engine be just as bad in hot weather as in cold?

Ideas??

Just a thought...I may be reachin' here: are your motor mounts in decent shape?

I've had a similar problem on another vehicle of mine. There is no consistancy or pattern and it has only done it a couple of times. The knocking sounds like the noise you get when you are trying to accelerate the vehicle in too low a gear, as in a manual trans. Is that the same as yours? Anyway, I suspect the cause to be too little fuel from the injectors on start-up so that there is not enough power to properly push the pistons for a second or two.

I had that same thought... they look fine and the engine doesn't move when you hit the starter. I would be shocked if they were giving me trouble only in the cold weather. I bought the high end purolator filter with the good anti-drainback valve and some synthetic blend oil. We'll see if that helps, but I won't really be able to tell for a while because it supposed to warm up this week.