510rider

New Plugs, Sea-foamed, grounded good, new PCV installed. Will stall at lights and signs at idle, at speed it drops about 500 rpm. Thought it was a transmission problem at first. Tonight it misfired worse than it ever has while going to dinner. Had to keep my foot on the throttle at stops to keep it from stalling. At speed it misfired like every 50 yards for miles. After dinner started it up and it drove perfect!! Went to auto parts store to see if it thru a code, nothing!!!

Has anybody else ever experienced this??? Crank Shaft sensor on the way. Might as well start changing sensors. (NGK plugs by the way).

HELP!!!!

Seizer

I know a Ford Focus is nothing like a JK. Had a similar problem with it and it was the intake manifold on the Ford. It was cracked. Ford made the manifold plastic......

Another car I had owned it was loose vacuum line and acted like you have stated.

Sorry I don't have more useful input for your situation.

510rider

Changed the Crank Position Sensor because it was cheap and easy!!! It's been 2 weeks and not one misfire!! Runs perfect. It never thru a single code!!
I hope this helps someone in the future who may experience the same thing!

rob_engineer

Hmmmm. My 2012 developed a very occasional momentary stutter. Would only happen once or twice a month. Only lasted about one second. Always happened at low rpms when getting back into gear. Another person on here had the same issue. Neither of us had any codes. We both replaced the crank sensor and the hiccup went away. I assume somehow our issue is related to yours.

Rednroll

I know I'm going to start sounding like a fanboy, but before dismissing that there weren't any codes especially for a confirmed sensor related problem, I would be more suspect of the OBDII scanner than there not being any codes. Unless you took it to a dealership and they told you there weren't any codes. I got the BlueDriver OBD2 scanner for this exact type of reason. The one time I needed to read codes for a problem, I used Torque Pro and nothing showed up. I went to 2 separate autoparts stores and had them pull codes and nothing showed up. I got the BlueDriver scanner and suddenly the codes I needed for diagnosis showed up.

Heck, it even pulled codes from the Infinity amplifier that didn't show up using Torque Pro that indicated that 2 of the audio output channels had an open circuit, which in fact it did because I had removed the factory rear sub-woofer.

The 5 wireless Control Module codes indicated in the image below are 1 for each of the wheels (4 total) for the TPM sensors I removed, and then an additional WCM configuration mismatch code, which got logged due to using my Flashcal to turn off the tire pressure dash light. None of that showed up when using Torque Pro in the past.