Misfire at idle

STALLY

MEMBER
2004 FORD EXPLORER
6 CYL
2WD
AUTOMATIC
82,000 MILES

Everything Started with a Leftside Lifter click and check Engine Light on, I changed Oil to Synthetic and Filter, Added Sea Foam and STP Oil Treatment, 10 days later the clicking went away, then the Rough Idling started and the codes P2198, P0300, P0312, P0306 o2 Rich Bank @ Sensor 1, MisFire Cyl 2 and 6 showed up. Then I Added a Lucas Gas Treatment, Changed Air Filter, cleaned out the EGR Valve Air Intake area, and Changed all the Spark Plugs to Bosch Platinum pre gapped, and the check Check Engine Codes and Light went away but it Still Idling Rough when at a stop or Low Idle position, motor almost stops. Why? Is it a Bad Lifter, Spring, Coil. What do I check for or need to replace next. Any Engine testings available?

6 Replies

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

Hello,

This sounds like you have low compression in one or more cylinders lets start by doing a compression test here is a guide to help you.

https://www.2carpros.com/articles/how-to-test-engine-compression

This guide can help as well

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down these guides and report back.

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Monday, December 21st, 2020 AT 11:18 AM

STALLY

MEMBER
3 POSTS

Is like a MisFire, on Low Idle is when the engine vibrates, shakes and almost dies, a a once in a while stall, all these only while the engine is on low idle, at a stop light, parked. Not while driving or high idel.

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Monday, December 21st, 2020 AT 11:18 AM

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

If it is only at an idle, I would say it is either a vacuum leak, idle air control valve, or throttle position sensor. Since it goes away when you give it gas, the idle air control valve is more likely. Has the check engine light ever come on?

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Monday, December 21st, 2020 AT 11:18 AM

STALLY

MEMBER
3 POSTS

This 2004 Explorer V6 came with an Automatic IAC (no IAC Sensor) so the question is out about cleaning or replacing the AIC Valve, The Engine Miss, it has Low Idle at a halt position while running (ex; Parked, at a Red Light, in Traffic) and it even shut off once when I was slowing down at a stop sign. No Check Engine Lights or any other lights comes on. Is just that Engine problem previously mentioned. I do not see any lose or out of place hoses, leaks or funny noises, the only noise is at the rear muffler tail pipe that sounds like is sputtering, missing, gasping, choking something like that sound. Does The Car has Bad Gasoline? Is it electrical? Air? Bad Injector or O2 Sensor?. Thanks for your time.

Stally
derby90@yahoo. Com

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Monday, December 21st, 2020 AT 11:18 AM

JACOBANDNICKOLAS