Desperate for Guru... vintage Camry

Thank you in advance!!!
99 Camry, 170 miles, historically perfect.
A dream car.
Maintained religiously.
But she dies.
Usually after a stop from downhill but i am too skeered to test her under any other conditions.
Starts up immediately…drives fine.
Then she dies again.
My Magic Mike the Mechanic cannot find the prob.
No warning lights, no help from the diagnostic computer thingy.
NO other issues.
He cleaned the starter motor ? thingy twice, but as I drove out the station i could feel her wanting to stop.
And she did.
I am desolate.
Cannot buy another car. Ever.
Lurked on the Net at length, this is not an unusual vintage Camry problem but found no definitive answers.
Please help…
Thank you thank you thank you

It’s losing spark or fuel…First, you must determine which and then fix the problem…

Likely suspects are fuel pump, fuel pressure regulator, ignition module…First, try changing the fuel filter and cleaning the MAF, mass airflow sensor, located inside the air-intake duct just downstream from the air filter…The TPS, throttle position sensor should be checked too…

Does it die primarily when at idle - meaning does it run OK above idle?
If so, then
1: check the IAC (Idle Air Control). They can be removed & cleaned in less than an hour.
2: check your EGR valve for proper operation - thought that should throw a light if it’s not working properly.

Else, Caddyman gave you a number of good suggestions above.

I’m betting on a fuel pump. If you can make it do it driving down hill, then the mechanic can put a pressure gauge on it and watch it while it fails.

Could also be bad ignition switch.

Caddy’s advice is solid… Start with the fuel filter.

I don’t buy the fuel pump or filter, they usually cause problems first at high speed, under acceleration or going uphill. Also what the heck is a “Historically perfect 99 Camry”?

Your Magic Mike needs to be replaced.
Running engines die because they lose either fuel or spark. The cause of the loss of either is readily diagnosible, but it requires the abillity and the knowledge to test the fuel pressure and the spark.

My guess based on the age and mileage is the fuel pump. But it’s only a guess. It needs to be diagnosed hands-on.

Sorry. But it has to be looked at. There are too many possible causes to guess.

Is this car dying for lack of throttle? Are drivers no longer using the accelerator to keep engines running when the idle speed drops down so slow that the engine stalls? Is the OP making no effort to overcome an obvious slow idle speed stall? That’s what it sounds like. Cleaning the throttle and IAC, checking the intake for vacuum leaks, etc., might result in a cheap and simple repair.

@littleblakdogs, does it seem that IF ONLY THE ENGINE WOULD SPEED UP A LITTLE IT WOULDN’T DIE?

The way I read it, the problem sounds like an Idle Air Control valve issue to me; or possibly a vacuum leak which could be causing the IAC to act a little stupid.

First, I’ve never seen a fuel filter cause a running problem on a Toyota, nor a tps sensor, and it doesn’t even HAvE MAF sensor, it has an iat and a MAP sensor. Neither one is the problem anyhow. Have your mech press up on the egr diaphragm and it should stall, it should Also not stick and restart when you hit the key, and not stumble. Egr valve sticking is common. You need a scan tool that can perform an active test of the iac valve. It should respond smoothly and not stick. Lastly, and less common, assuming its a 5 cyl (u never mentioned) it cold he a bad ign coil. All 3 won’t necessarily set a code. I think based on your description, it’s an idle air control issue. But if someone has to clean your starter motor twice , it’s either the Iac he cleaned or he’s a moron. I agree that if you were to give it slight throttle when it’s bogging down, and it’s better , that’s a sure sign of a bad iac. Replace it if that’s the case.

.*4 cyl , not 5

I could be wrong, but i don’t think this engine HAS an in line filter. I believe it has an in-tank self-cleaning filter.
I KNOW it doesn;t have a 5 cylinder… :-).

Based on a 96 (V6) it could be a dirty throttle body that is keeping the throttle from closing enough to tell the computer, via the tps, that it is supposed to take control of the idle speed. Cleaning the throttle body might do the trick.

Many many thanks to all for time spent…printed out everything- except the unnecessary nasties- to give to MagicMike.

"historically perfect’ by the way means: in my experience, flawless
Adv. 1. historically - throughout history;