Question about Fuel Injector Noise - Stalling/shuddering Camry

Hey Everyone!

Normally I spend more time answering questions than asking them, but this time around I need your advice:

The vehicle in question is a 92 Camry LE, with the 3.0 V-6 engine, and it belongs to my gf’s 18 year old daughter.

The problem with the car is that as it is driven, the engine performs sluggishly, and when brought to a stop, and idling, it shudders/idles rough.

I’ve changed the cap, rotor, spark plugs, spark plug wires, and performed tests on all the EGR hoses that feed off of the throttle body, cleaned the throttle body, and made sure the idle speed control system works as designed.

In my most recent attempt at getting a clue as to what is going on with the engine, I popped off the front valve cover, and checked the valve clearances, all of which were on the loose side (not bad for 172k miles).

After putting the valve cover back on, I decided to move over to the fuel injectors, and whipped out my trusty long screwdriver, pressed it against the fuel injector body while the engine was idling, and listened to 5 of the 6 injectors ( I could reach the center injector of the rear bank because the intake plenum is in the way).

4 out of those 5 injectors made a nice healthy ticking noise as the car idled away, indicating that the pintle was slamming shut when the solenoid is de-energized. That 5th one, however, seemed quiet in comparison.

That one is located on the rear bank, on the fan belt side of the engine.

My question is probably two-fold:

Can a fuel injector still be good, and be silent, while all the others tick?

Does this sound like a reasonable diagnosis for the troubles the car is having?

There are no CEL’s associated with the car.

When I get home, if the daughter and the car are still in town (she lives 60 miles north of us), I was planning on disconnecting the fuel injector connection, and seeing if there is any change in the way the car runs as a quick test, plus also to see if there’s any corrosion, or a loose connection.



May be the perfect time for a can of Seafoam!

One of the diagnostic methods of determining if an injector is the problem is place a mechanics stethoscope on each injector. If the injector makes a sharp clicking noise it’s good. If the injector makes more of a thudding noise or no noise at all there’s a problem with that injector.


Actually, I have tried Chevron Fuel system cleaner in the past, but it didn’t make any difference, according to the driveability of the car. If the fuel injector is bad, that would make perfect sense why it didn’t help.


Yep, that’s basically the point I’m at right now.
out of the 5 injectors I can reach, 4 are ticking along happily, and the 5th is pretty much silent.

Can an injector be silent, but still be functional?
I think not, but am going for the group’s consensus on this one, before I throw money at a part that might not be bad.


If you had a noid light you could plug into the injector plug and if there’s a pulse signal to the injector. If there is then the injector is bad. If there is no pulse signal then there’s a problem with the wiring or the injector plug.