Hesitation on take off

[fred]

I have a 2007 Nissan Sentra 2.0l S. When taking off from a stop or after hitting brakes and then resuming speed car hesitates. Of course there are no codes. I have changed fuel pump . Car has 200k miles on it. Thinking of changing plugs next. Oh yea cleaned out the mass flow sensor. No effect. Any other suggestions would be appreciated.

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[Richard Kirshy]

Might inspect the coils for carbon tracking.

[fred]

When i changed plugs at 100k i noticed a liittle oil around one of the plugs. Could this possibly have gotten worse and causing my problem? Guess I will change plugs when I get a chance and change intake maifold gasket and valve cover gasket since i assume that may be where the oil leak is coming from.

[Richard Kirshy]

Spark plug wells full of oil is never a good thing.

[fred]

I will check it out this weekend

[Keith Kachelhofer]

I had the same problem with a 1992 Honda Accord. There was oil in the plug wells. The oil will deteriorate the rubber and the boot will break down causing an arc to jump over from the plug boot to the engine block. Mine were cracked really bad.

Have someone sit in the driver’s seat with the car at idle. Go to the tail pipe. Look for a faint trace of black smoke. Rev the engine to 1,200-1,500 rpm and see if the smoke is more prevalent. If so, then I would suspect incomplete combustion due to the plug boot arcing.

In my situation, the hesitation would only occur at lower rpm taking off from a stop. Once the car achieved an rpm of 2,500-3,000 rpm then it wasn’t noticeable. in my case, I originally thought it was a clutch plate slipping.

I suggest a good set of NGK plug wires and replace the wires and boots; unless you have a coil pack. Then replace the coil pack. Either way, you need to fix the oil leak into the plug wells. Recommend resealing the plug wells and new valve cover gasket with new grommets.

[Author]

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