Hello all.   I have a 91 sidekick, 5 speed.  When i first start it up when it's cold it idles up to about 2000 rpm, but then as it starts to drop down the engine developes a very severe shake until it warms up.  At this point after the shaking stops and the idle is still around 1400 rpm it will rev up and down a little bit.. maybe +/- 100 rpm.   Also, when I am driving around it feels like it is "jerking" or "serging" at a steady engine speed. Vehicle only has 105,000 kms on it and I have replaced plugs, cap, rotor, pcv, and have cgecked EGR and trouble codes are all clear.  

any ideas what this could be?  

Spark Plug Wires,
Mine did the same thing,
drove me crazy, my brother
said wires do that, started all
at once too, but that fixed the
problem.

thanks for the tip.  I've got another set I can try out.  I would think that plug wires would cause it to miss all the time though?  

oh well, worth a shot at this point.  

I'll post my findings.  

Ya thats what I thought too.
My Kick would start and idle fine.
even ran fine until I got up to
freeway speeds, then it felt like
it was surgeing, like all cylinders
would fire then just some, not
a stead miss, just real strange.

BTW my wires were stock and had
255,000 miles on them kick is an 89

Darrin

i think those were some prety good wires =) lol i still have the stock ones in my car also whats the limit on wires? like tires have a shelf life for about 7 years whats the life on plug wires?

I always thought high performance wires were hype
I've never bought wires until these, and I dunno the
life of plug wires, they have a shelf life  

this one runs great at freeway speeds,  its just in town that it bucks and farts.  .. i don't know. :-/

well if its farting give it beno that should take care of it...mabey some ex-lax will clean it all out so its spttuer free lol

My ex-gf had a Kia Sportage 4WD, had 120k miles on it with the original plugs and wires. It had the same symptoms you described with yours. We changed the plugs and had the wires/coil packs tested, and one of the coil packs was bad.