NA6 hesitation, 90% sure is not ignition related

mitch_f1 · Postby **mitch_f1** » Thu Nov 20, 2014 6:02 pm

So it only happens when it is cold, and mostly disappears within 10minutes of engine running. What will happen is if I have a constant throttle it will reach a point in the revs where it will kind of cease, and just coast, and then if i push throttle a little more it will jump forward and continue through the revs. If I lift off the pedal at this point the revs will drop back to idle but will be very erratic. It's almost feels like the throttle cable is caught on something, then it suddenly springs open.

Not too long ago I experienced the hesitation from worn plugs/leads, so they were all changed recently, and it is a similar kind of feeling to that, but longer.

Am I making any sense? Has anyone else experienced such issues?

bruce · Postby **bruce** » Thu Nov 20, 2014 6:13 pm

Plug leads.

mitch_f1 · Postby **mitch_f1** » Thu Nov 20, 2014 6:14 pm

As above they are virtually brand new, and does not feel like the same hesitation as it did before.

speed · Postby **speed** » Thu Nov 20, 2014 8:46 pm

This is just a dodgy guess, dirty throttle body or IAC or temp sensor in air flow meter?

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JBT · Postby **JBT** » Thu Nov 20, 2014 8:53 pm

Disconnect the throttle cable and check that it moves freely through the full range. The inner cable could be frayed and catching on the outer cable sheath.

a222133 · Postby **a222133** » Sat Nov 22, 2014 3:42 am

I go with Speed ! similar experience on my NA at about 250,000 k

mitch_f1 · Postby **mitch_f1** » Sun Feb 01, 2015 6:38 pm

So I used an upper engine cleaner today thinking that that might fix up the issue, but not. Here is things it is not:

-Plug leads: next to new, measured resistance, all way within spec.
-Spark plugs: although not measured, all are next to new
-Dirty sensors: Oxygen sensor replaced not long ago. NA6, so no air intake temp sensor (that I know of?)
-Air valve: inspected and is clean, have not tested function though
-Throttle cable: moves freely

I've done some more testing and I've found that it really only happens between cold and operating temperature. Once it is at operating temperature it is fine. It only happens at around 2,500rpm, and only if it hovers there for a moment. If there is a bit more pull in the revs then no issue; only seems to be an issue if the revs are pulling slowly, or if acceleration hesitates at around 2,500rpm. Doesn't seem to be an issue at speeds of >70kph, but will test this further, is certainly not as noticeable if it is.

Please, any help is appreciated.