Car is a 1985 IROC with HO motor, carbed, stock. Car has 42000 miles on the clock.

The car won't idle when it's cold, and while the car is warming up, it stumbles upon acceleration. It feels very sluggish and heavy. I expect the car to be sluggish while cold, but the stumbles have me concerned. After the car is warm, it runs and idles perfectly, with power that I would expect from a warm engine.

P.O. put on some junk headers, but it looked like he loosely fitted the headers, welded them into the stock y-pipe/exhaust system and tried to tighten the headers down. There was a pretty large exhaust leak around #'s 4 and 6 exhaust port. Yesterday I replaced the headers with Hedman shorties, Hedman y-pipe and magnaflow 3" catback. I replaced plugs and wires while the swap was going on. I also replaced the O2 sensor with a new one. Everything was reconnected except for the following problems.

1. There was a large hose running from the carb vacuum lines to the charcoal canister that was badly deteriorated. It tore in half. I have not replaced this hose, partly because I cannot pull it off either fitting (at the carb piece or the canister). I can cut this off the fitting and replace it, if this is the problem.

2. There is a sensor between plugs 6 & 8. This sensor has a single green wire going to it, and what looks like a metal barb in the center of the plug. This is one you squeeze the sides of the plug to remove it from the sensor. What does this sensor do? I am having trouble getting the plug back on as well.

Any suggestions are welcome, it's raining today, so I'm trying to do a little book trouble shooting on these issues.

 

The vacuum hose should definitely be replaced. The wire connector you're referring to is the temp sensor for the fan. It too should be plugged in if you don't want overheating to become an issue. As to your original query, it sounds like you have a choke issue. Have a buddy start the car while you monitor the carb throttle plate. It should be almost completely closed. As the car comes up to temp, it should slowly open to allow more air in. After it's completely warmed up, the plate should be open all the way.

 

Any suggestions on getting that sensor plug pushed on? I've tried squeezing the sides, wiggling it and twisting it to try and get it seated. The only thing I haven't tried is an attitude adjuster.

 

It should just be a push on connector. Look up a temperature sensor connector for your year of car on jegs or summit's website and you should find a pick of the sensor. Make sure yours looks like it. There's a stubby piece that the wire fits over that should have a shoulder on it that the plug snaps onto. If it's not there, then you'll have to get a new sensor.

 

IROC,

You're right, the stubby piece isn't there. Thanks for the help.

Btw, the car started and ran fine cold this morning. I don't know whether the sluggishness was a fluke or not.

 

it might've just been a case of the fuel pump not pressurizing the system to make it start happily that first time