Is there a way to get them w/o an OBD II reader ? Like when you cycle the ignition switch and count the check-engine-light flashes on some vehicles ?

Reason I ask is yesterday it suddenly started running rough. You could hear and feel it. I'm thinking a fouled plug or something. I'd like to be able to get an error code to be sure I'm on the right track.

The check engine light has not come on.

Also, is there a trick to replacing plugs on the 3.5L ?
I pulled one (it looks OK).
The coil comes off easy enough but getting the rubber spacer out was a pain, and I'm thinking getting it back and with a good connection on the plug, is going to be worse.

Any hints ?

- seen in FOUR WHEELER mag July 2006 & OFF-ROAD mag Feb 2007 -
'84 4Runner ARBed 5.29s F&R,4.7 & 2.28 t-cases,hy-steer,BudBuilt skid,30spl Longs,36" TSLs,Chevys

'83 P/U, Buick 231 V6,Holley 4 bbl,Weiand intake,Downey headers,TH350 w/700R4 gearset