My '97 ran perfectly until this morning. As I drove down my street, it stalled as I got to the first stop sign. Its stalling every time I come to a stop. It has a loopy idle, up and down then zooms up to 2000 rpm then down to 0 stalling.
When I restart it, it does it again. I've got to shift into neutral and give it some gas to keep it from stalling at stops.

Any ideas? IAC valve or fuel pressure regulator? It ran fine yesterday when I parked it.

Its not my daily driver, just a summer car so it sits most of the year. I filled it with new gas today but that didn't make any difference.

 

When was the last time the fuel filter was changed, outside the Car under the passenger seat, looks like a beer can with the fuel line running in and out. Caution when you remove the nuts on each end takes an open end wrench. Also you may want to check your vacuum line from the engine to the firewall at the Master Cylinder. It could also be the CAT Convert might be full and blocking the exhaust.

 

This surging/stalling happens when the engine is "cold", right? ("Cold" as in hasn't been running for at least an hour.) My '95 used to have the same problem, until one of the deep-freeze, single-digit cold mornings of last winter did something to the engine, and that surging/stalling problem went away -- and the cold-start idle has behaved ever since, always hanging around 1000-1200 rpm now.

I realize this is one of those "car problems that fixed themselves", lucky for me, but from what I've gathered, it's a vacuum leak problem that's fairly common on the LQ1. Some people say it's one of the intake gaskets leaking, or it could be the vacuum line that drivernumber3 is suggesting.

 

Well I found a cracked and loose rubber fitting at rear of the valve cover that goes via a plastic tube to the throttle body. I taped it up real good and started the car. It idles fine now, a little up and down, but nothing like the trouble I had over the weekend.

I'm not sure that's a vacuum hose, I think its more for venting gasses back into the throttle body to be burned off. Emissions system? So I'm not sure that was the actual problem.

 

Yeah it's off some evap component. But yes, a leak in that hose would be a vacuum leak. Tape works in the interim, but definitely get another hose when you can.

 

If I take off the hose it doesn't seem to make any difference in the idle. Car seems to be running fine now though, I think I'm going to replace the IAC anyway, can't hurt. It was a really hot day when the trouble started, maybe the valve stuck closed or something.