I had the water pump replaced several weeks ago. Last week while stopped in traffic the car just died; no rough idling and it started right back up. This afternoon it did it again. Any idea as to what the cause could be? No check engine light, but it may not be working. I had the computer checked for codes shortly after the water pump was replaced (mechanic had knocked a vacuum hose loose) but there were none. Plugs and air filter were replaced 5/2016. Battery replaced 8/2014. Distributor “rebuilt” and spark plug wires were replaced 1/2013…
If only at stop it it is possible a vacuum hose got accidentally disconnected or broken.
Check the engine oil, coolant, and transmission fluid levels first. Check the coolant in the radiator too if that’s possible, not just in the plastic overflow bottle. If those are ok, my guess is you have a problem with your ignition switch. Try driving the car with just the single key in the ignition, rather than on a key chain. If that improves things, most likely you need a new ignition switch. Suggest to have the diagnostic codes read out too. If you have some now, post them here. Just b/c there’s no check engine light doesn’t imply necessarily there are no codes.
Since the distributor was rebuilt, the ignition control module can be ruled out.
When engine just shuts down, it can point to a faulty crankshaft position sensor.
If the computer loses the signal from this sensor, the computer see’s no reason operate the fuel/ignition systems.
It usually starts out with engine stalling out every so often, then more often, then the engine won’t start until it cools down, and then engine won’t start at all.
It could even be the same vacuum hose that the mechanic knocked loose. If that hose has lost its elasticity sufficiently for the mechanic to knock it loose, it probably no longer has a good hold on its tubes and may need replacing. And if one does, they all do.
Truth is, there are a lot of possibilities here including but not limited to a worn out engine. You might want to do a compression check on it before making any assumptions. A vacuum gage can tell you a lot about how the valvetrain is running also.
Fuel pressure test is another good idea. If the pump is failing you can have erratic operation, although usually this shows up at speed.
Another possibility is the Idle Air Control valve acting a bit flaky. That is not unheard of with any make of car.