'89 Civic LX - Bad stutter

I have a '89 LX Civic with a D15B engine, Carb, 5 spd. 220'000kms. NZ
assembled, no emission control etc.
Often lately, under light load, the engine violently stutters, once loaded
up, irrespective of rpm, it runs fine.
The problem usually goes away if left overnight, but not always. Most of the
time this happens when the engine has been at operating temp. for a long
while, but may still be there even after hours of cool down.
Car has been fairly well maintained, but nothing had be done immediately
prior to the problem first time.
Any ideas on where to start looking? I'm on a budget, so I'd rather not use
the hit & miss theory by replacing parts until I find the right one.
Thanks in advance for any help.

Greg.

 

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Cheapest thing to try is a couple tanks of gasohol, if available in your
area.

Check both ends of your negative and positive cables, and especially the
grounds to the chassis from the engine. The 'light load' part caught my
eye. Poor grounding can show up worse if engine is sitting straight, not
'leaning into' it.

You may have to unbolt the ends to see if corrosion has gotten under.

'Curly'

 

Totally agree with Curly - those are the same things that came to my mind.

As another inexpensive thing to change, I'd also change the fuel filter -
those can cause weird things like that too.

Hope you nail it soon.
Remco

 

Unplug the EGR valve and drive see if it makes a difference. Sometimes when
the EGR control unit starts to fail, they open at the wrong time.
Steve

 

Does this engine have an EGR valve? Where can I find it?

Greg

 

Check the spark plugs. May have an oil leak from the valve cover that
has worked its way up into the plug wire, or too much gap. bob

 

Most all engines from the late 70's have a egr valve, somewhere.
It's somewhere on the manifold, you have too unplug a vacuum hose and plug
it.
Being it's a NZ motor I don't know if it really has one
Steve