[net.auto] Help needed with Omni, please

geopi@hou2e.UUCP (G.COTSONAS) (01/03/86)

Car:
	1981 Omni 1.7 liter, 39,000 miles
Problems:
	Engine misses severely, very severely;
	gets up to highway speed, but only with much coaxing.
	Especially pronounced under any load or acceleration.

	Friend, who is automotive guru, worked on ignition system.
	I now have good plugs, wires, rotor, cap.
	Claim is that ignition is performing well now, though we haven't had
	access to a diagnostic analyzer;
	one plug did seem to indicate lean condition.
	Condition of spark control computer is anybody's guess...
	Car runs as poorly as before, or worse.

	Friend (aforementioned guru) suspects carb now.
	A complication is in that my exhaust system
	came apart at the catalytic converter,
	and it is now patched, but not welded up yet.

Questions:

Is a carb overhaul in order?
Could the problem be with spark advance, or computer control?
Could backpressure problems related to the exhaust affect performance
	so severely?

I realize that this information is skimpy, and diagnosis over the net
uncertain, but would appreciate any wisdom about the Omni which
you could share.  I have had it six months, with all too little reliability.