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Stalling, Hesitation and Rough Idle on a 2004 Toyota Corolla

I’m having issues with my 2004 Toyota Corolla with 118K. Every few weeks, the car will go through a phase where it will stall out, run rough and hesitate on acceleration. Oftentimes it is accompanied with the rotten egg smell coming from the catalytic converter. When I decelerate to a stop light, the car will stall. When I start it back up, I have to rev the engine to 2000 rpm in neutral to keep it from re-stalling. Once I get up to about 10-15 mph, the car will jerk and sputter, and at 40mph, the jerking motion gets worse. If the car doesn’t stall it’ll run rough and have the rotten egg smell. I’m assuming the smell is from unburnt gas.

I find it happens more often when I don’t let the car warm up for a few minutes.

I’ve taken it to my mechanic, and i’ve gone through 2 MAF sensors, cleaned the throttle body. I changed the iridium plugs at 102K and am on top of maintenance with filters, oil and such. Of course when I bring it to the mechanic, the problems don’t show up, and we are kinda blind to what could be causing the issue. Also, if I park it for a day or two after the issue occurs, the problems go away.

Any suggestions as to what to look for?

Another cheap thing to clean is the EGR valve. It often comes off easily and can be cleaned with throttle body cleaner. They rarely need to be replaced but they do tend to clog up.
I’m not saying that this is definitely the cause of your problem but it could cause what you’re describing.

I can definitely look into it! I changed the PCV valve at the same time as the plugs, but I must have overlooked at least cleaning out the EGR.

Vacuum leak
Air filter
Idle Control Valve (IVC)
Camshaft position sensor (CPS)
Bad coils (post 150k miles?)
Fuel filter.
Valve cover gasket leak
Blown head gasket

I had an engine code come up that the fuel mix was too rich. I also found out my car doesn’t have an EGR valve. Could it be the Vacuum Switching Valve (VSV)?

Yours doesn’t have an EGR? Is that a car built for Japan or something like that? They don’t use EGR there, from what I hear.
The VSV works in conjunction with the EGR. The VSV actually overrides the operation of the EGR when it is deemed necessary by the car’s computer.

Do you have a repair manual to your car? I’d try to identify all the parts under the hood to make sure you don’t have one

I went to Napa and they didn’t have an EGR Valve listed on the computer for my car, my Haynes Repair manual doesn’t list or mention an EGR valve, and I can’t seem to find anything online about an EGR for a 2004 US model Corolla.

Had a similiar mal function with my Dodge Dakota. My actron analyzer said Bad oxygen sensors. Replaced both upstream and dowstream sensors and problem solved.
also 95 new yorker similiar (rough idle) replaced idle air control motor (solenoid)
Did you do a diagnostic on it. Checked fuel pressure. bought my test equipment atHarbor Freight.
Some dealers will actually let you see their factory manual!!!

Ah, Napa. The ones near me are nice guys but they really don’t know cars.
You can often get a very good copy of the mfr service manual on ebay for cheap (maybe $10 shipped). Some can even be gotten online for free.
Even if you never intend to use a spanner in your lifetime, it may help you identify what’s under the hood and when someone tries to pull the wool over your eyes.