Rough idle

[schaff70]

My 90 Camry V6 was running fine on Wed when I got home from work. Left Thurs morning & it started running really rough, almost like it's not firing on all 6 cylinders, or has a fouled injector.
I replaced the dist. cap & rotor, but it didn't help. I'd like some advice on where to look next? I don't have a timing light to check the plug wires. Does the car have an EGR valve?
Also, any tips on changing the plugs near the firewall?

Thanks for the help.
-Todd

[Doctor J]

The US speck engine HAS EGR valve
I would lok for possible large vacuum leak in the air inke boot between air flow meter and throttle body and pcv valve hose.
If no vacuum leaks are found, the power balance test is next step, however it is very hard to pull the spark plug wires from the rear cylinders.

[schaff70]

Can you explain the power balance test?
I've pulled plug wires from a V6 in the junkyard, but never installed them.
Any advice on changing the spark plugs?

[Doctor J]

The old-fashion method is to pull spark plug wire by the boot off the spark plug with insulated pliers one at the time from idling engine; if engine is NOT running worse when plug wire is disconnected the cylinder is faulty. The better method is to unplug the fuel injector electrical connector one at the time cutting fuel delivery to one cylinder at the time [I used this one on 4 cylinder Camry].
The professional shps using scope machine to determine fauty cylinder.
Make sure you Ohm out the used wires you have, they should have no more then 12 kOhm resistance.

[schaff70]

I wound up picking up a set of new plugs (NGK) and wires.
They weren't too bad to change, mainly because I have small hands, although my right hand did get a little shredded working on the back plugs.
I did my best to measure the resistance in the old plug wires (having never used a multi-meter before).
The old plug wires were registering around 4.6 (k)Ohms (?) and checking against the new wires (10.4 K-ohms) I'd say the old wires were close to being shot.

The car seems to run smoother now.

Is there a trick to removing the rotor? I wasn't sure if it was held in by anything & didn't want to damage something.

On the down side it looks like I need to take care of the valve cover gaskets & I'd like to replace the O2 sensor as well (185k miles). I've seen a variety of O2 sensors online and would like a brand & part number for a direct replacement instead of a 'universal' part.

Thanks for the help guys. I'm used to working on much simpler engines (Volvo B210/B230/B234) with much more room in the engine bay.