Hello Everyone. New to the forums. Having issues with my 2003 V6 Solara. I'm getting a rough idle at cold start that I'm trying to iron out.

Cleaned Throttle (on car / no disassembly), IACV, MAF
Checked for vacuum leaks (physical inspection / sprayed starter fluid on lines)
Replaced Coolant Temp Sensor (next to radiator cap)
Air filter was replaced a month ago

It's gotten better than when the problem first started and I began trouble shooting. When I first start the car in the morning, the engine stumbles. CEL flashes or stays on some days. When the car comes to operating temperature the car runs normal. I clear the CEL/Codes, restart my car and then I go about my day. The codes I'm pulling are P0300, P03001, and once and a while, P3002.

I believe the coils are actually good. If they were in fact bad, the code would return during driving (someone correct me if I'm wrong).Like I said, once the engine reaches normal operating temperature, the car runs fine with an idle of just under 800. Is there anything else that I'm missing?

I've also noticed that the FSM references two ECT sensors. The one that I just replaced next to the radiator fill cap, and one that's on the water inlet tube going to the thermostat. Looking on the Toyota Parts sites, there are 3 that are available one for E.F.I and two that are categorized as "Temperature detect"

I don't want to replace expensive sensors if I don't need to but if there are people out there with some insight it would be greatly appreciated.

Thanks in advance.

 

There is a temp sensor on the passengers side mid engine.

Might have Brown and Green/Black wires.

 

That's the one I replaced with no difference. I'm going to replace the driver side one located on he water intake tube and I'll let you know if that makes any difference.

 

Here's the list of items that can contribute to your P codes.

Injector
Fuel line pressure
EGR
Compression
Valve clearance
Valve timing
MAF
Engine coolant temp. sensor
Open/short in engine wire/connector connection
ECM

If the check light is flashing there is a major misfire that can cause damage to the emissions converter. Would suspect an ignition issue. Coil, plug, wiring, etc.

 

Just an update. I did a tune up just to be thorough. I changed spark plugs and ignition wires. I noticed that cylinder 1 had white residue on the plug boot when I removed it. Also the connector got stuck on the spark plug and separated from the boot. So far so good as far as start up and idle go.

 

Great job. Thanks for the update.