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[url=https://imoc.co.uk/app.php/kb/viewarticle?a=22]Knowledge Base - How to solve hesitation, missfires and flat spots[/url]
This comes up a lot so I thought I would do a little write up on it.
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Feel free to add to this if you feel I have missed something out!
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Hesitation and flat spots are generally caused by poor ignition components.
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I have recomended things to check in the order that they are likelyest to be and the cost of replacement.
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1.
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Check the distributer cap and rotor arm.
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(see separate how to for replacing them) If the contacts are heavily corroded or damaged replace them.
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Check for signs of oil or water in the distributer cap.
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Whilst you have the cap off.
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.
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.
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.
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.
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2.
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Check the state of the connectors on the HT leads, look for corrosion or damage to the contacts again.
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3.
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Check the state of the ht leads in general, look for splits in the leads, kinks and check the connectors at the spark plug ends.
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.
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.
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.
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whilst you have the ht leads out.
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.
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.
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.
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.
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4.
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Check the state of the sparkplugs.
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.
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.
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.
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look for wear on the electrodes, damage or discolouration
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5.
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Check the airfilter.
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.
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.
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.
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replace
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/ clean if dirty
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6.
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Check the ecu for error codes and perform an ecu reset.
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If these all look ok but you still have a flat spot I suggest:
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1.
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Replace the dizzy cap and rotor arm first
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(around
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£20 for the pair from mrT)
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2.
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Replace the sparkplugs next
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(NGK\'s cost about
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£8 for 4 from unipart)
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3.
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If the problem is still there try some injector cleaner
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4.
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I suggest changing HT leads last of all as these don\'t tend to fail very often and are very expensive to replace!