New ZR-1. New Issue. Stalling Once Warm.

[Erik]

Don?t it always work that way. A few days into my ownership (or does she own me?) 996 started acting up.

For the first few days, I just took it easy. Was gonna get it in to the local Corvette guy for an inspection anyway. Started off with some short rides. As I got more comfortable, started expanding the range a bit. Finally was getting pretty comfortable so did some shopping, kicked a round a bit, and went and gave her a fresh tank of premium. Shortly after filling up, she coughed once. Not a backfire, but what felt like a fuel system cough. Meh, old gas working it?s way through, I thought. Got home ok. Parked for a while, and thought I?d taken her for a short run before dinner. As I?m toddling around, she coughs again. Then a few more times. Then a stall, starts up ok. Then does it a couple of more times. This is all slow speed, low gear, in the neighborhood stuff. Finally manage to nurse her home, and sent her off to the mechanic by flatbed to get the planned check over done.
Now, before the fresh tank of gas, she had run fine. Hadn?t pushed her to the redline yet, but 6000 rpm pulls felt good. Felt very smooth under power. Idle was ok. Seemed to want a couple of seconds cranking, but I?m used to modern cars that start so quickly, that the slightly longer cranking time might just be me.

Took her to the mechanic, and the good news is that all the mechanical stuff is good. Brakes, suspension. No oil leaks. Good structure. Nice, well kept car.

The bad news? It?s still doing the weird idle and coughing thing.

Here?s what it does:
-cold start. Starts up ok. Idles smoothly. No issues
-runs great until warm, then it starts running rough and wants to stall.
-give it gas. Keep it over 1000 rpm and it feels ok.

I had bought some parts for winter time projects, but it seemed a good idea to use them now. So, we replaced:

-Both fuel pumps, with New Delco ones. Socks, tee, etc
-Fuel filter
-spark plugs - just because. Idle smoothed out with new plugs in.

I spoke to Marc Haibeck on the weekend, and his first thought was fuel too.

Mechanic is gonna drain the tank today and see what it looks like in there. Not a lot of use over the past decade, so it could have a fair pit of crap inside.

Btw, the injectors were replaced by the previous owner.

Yes, when It was acting up, it sure felt like fuel. Maybe a bad carburetor?

Appreciate any thoughts.