I was just thinking about my last smog check and I had literally 0.00 NoX and 0.01 on the other measurement(forgot the name ).

Anyways, my Hydrocarbons were a little high and i was wondering if this was related to me getting below average MPG....so, isn't HC's like unburned fuel??? Could my injectors be leaking?

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-Dan
-1990 3.1L RS
-Mods? no
-Slow? yes
-Currently collecting parts for T5 swap

 

hc is unburned fuel. Could be several things. Incomplete combustion misfiring plugwires/plugs is the most common cause.

 

Right... high HC [i]and[/c] high CO indicates a rich mixture, i.e. too much fuel for the amount of air. High HCs by themselves along with low CO numbers indicates that when combustion does occur, it's in the right proportions, but unburned fuel is passing through the engine to the exhaust. In a stock motor (no big cam, no blower) this is usually caused by an ignition miss.

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"So many Mustangs, so little time..."
ICON Motorsports

 

RB83L69,

Ok, what i've observed is that when my engine is cold/warm it runs fine. When it gets up around 220 i notice my tach move up and down EVER SO SLIGHTLY. Not much, but it's visable and audible. I have new plugs/wires/cap/rotor....what should i replace?? Ignition module?

Oh, and a miss wouldn't explain poor MPG's....right?

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-Dan
-1990 3.1L RS
-Mods? no
-Slow? yes
-Currently collecting parts for T5 swap