I took my 88 IROC (5.7TPI) onto the Nelsons Ledges Road Racing course a few weeks ago. I overheated the engine (that's a whole story in itself) and now have a miss in the engine now. It is not a constant miss, but rather an intermittent one that seems to reduce in severity when the engine is at operating temperature.

I have started replacing plug wire cables and plan to replace the plugs, too. However, I do not think that this will fix the miss.

One of the heat-damaged items is a hard vaccuum line that is part of the EECS. There are two hard vaccuum lines that run from the EECS charcoal canister in the left front of the engine bay. The thicker one runs to the throttle body and the thinner one runs to a vaccuum t-connector under the intake plenum. I melted through the thinner line from heat that radiated from the alternator brace (which bolts to the exhaust manifold - dumb idea). If I am correct, this vaccuum line is used to actuate a control valve in proportion to the vaccuum created by different engine speeds.

For a quick-n-dirty fix, I bought regular vaccuum hose with an inner diameter equal to the outer diameter of this hard vaccuum line and slid it over the hard line. It is not a perfect fit and the miss is still present.

In addition to the miss, there is also a fuel odor when the car is running, specifically on cold starts. This odor is not necessarily consistent.

Finally, my question:
Would a damaged EECS line cause the car to miss as I described? Or am I "barking up the wrong tree"?

Thanks.

 

I would suspect plugs/wires/cap/rotor before the vac. canister...

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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

Then it sounds like I need to continue on my current path. As time permits, I will continue to replace the plug wires and plugs. If this doesn't fix it, I will then replace the cap and rotor. I suppose I'll eventually fix it... Thanks.