2004 Mazda MPV started Idling rough in drive. I changed out the plugs, cleaned the MAF sensor and cleaned the IAC Checked for leaks and found none. Still runs rough in drive and park

SOURCE: 97 Ford Ranger 4.0L V6 Idles rough only when cold

Orand

Ther is a air Idle control valve located on the side of the throttle body. unplug it remove it spray it and clean it with carb cleaner replace it plug it back in and you will be a Happy person again.

Lugnut61

SOURCE: 1999 mazda 626 4cyl runs rough at idle , engine

You may have to dig deeper for a vacuum leak. It's possibly the intake manifold gasket. Try spraying some starting fluid around the intake manifold. Also try disconnecting the brake booster and plugging that hose, the diaphram in the booster could be ruptured, causing a vacuum leak. Check the PCV valve and hose too.

SOURCE: 94 camry. 2.2 fed emissions.

Before we both knock ourselves out with fuel injector testing. Hook up a Digital voltmeter (DVM) to upstream O2 sensor and lets see how she is burning. Remember positive lead of DVM to signal wire and negative lead to ground. Anything above 550 mV is rich anything below 350mV is lean. Be mindful that an exhaust leak the size of a pin hole in this region can cause a rough idle. A healthy reading should bounce between 550mV and 350 mV.
Next to test is O2 is working block off air in take making mixture rich and see what O2 says about it . Then pull off a vacuum hose (a lean condition) and see if DVM drops to 200to 300mV's.
Keep me posted.

SOURCE: 99 rodeo starts hard after is has been warmed up. Starts fine after it has been sitting overnight. Almost starts like it is flooded. Have changed O2 sensors, coolant temp sensor. Cleaned IAC

Hello, I usually work on Ford family Brands. There are sometimes 2 temperature sensors on engines. One is meant for the dash gauge alone and the other is for the Engine management systems.

You could have one of several problems. A starter can sometimes fail becauseof heat. You would need to do a draw test when the motor has been run to duplicate your problem. Autozone, Advance, and Oreillys are some of the free test places.

The cold start cycle is like an Electronic choke. If the temperature info is not reaching the Engine management controls then the vehicle will always be set for a cold start.

Lean conditions also can lock an engine. In order to get good mileage the Camshaft timing is advanced. If the engine has worn timing parts, the firing may advance beyond specs. You may be fighting compression and experiencing vapor lock. Try going up a Grade in gas Octane.

SOURCE: 2001 GMC Jimmy Idling rough

I know the post is old but this is for the people who have the same problem like me and still search the web for a solution. P0300 random misfire code, rough idle after it warms up and then exhaust smells like eggs. Check the plugs 5 and 6 should have black carbon (rich fuel) plugs 1 to 4 look good. The problem was for me the Fuel Pressure Regulator. You will have to remove the air plenum to get to the fuel injector spider. Not difficult just follow a repair manual. You should notice the intake under neat will have a blackened appearance for intakes 1 to 4 and 5 and 6 will look clean. The regulator is venting the fuel and it is running down into 5 and 6 hence the fouled spark plugs. The regulator is on the back of the spider and easy to replace the biggest problem I had was getting to the fuel lines to disconnect them. Runs great now.