Idle question

[crites_72]

I know this isnt a truck question but its on my wifes 82 z28 and if i dont get it out of the garage then i'm never gonna get to work on my truckl. the car will idle just fine as long as its in park. but as soon as you drop it in a gear it will cut out and die. i've tried switching carbs, fuel filters, everything i can think of. i've made sure its in time. its just a 350 motor with a mild cam nothing special just sounds good. when you have it in drive it sounds like the idle is to low and then it just dies. but will fire up again with no problems. right now it has a quadrajet on it but i've put a carter and an eldebrock. and another quadrajet on it and still had the same problem. a mechanic friend of mine drove it and said that it was the float in the carb but can all of them really be bad. any ideas would be great its really confusing me. thanks

[BigDaddyDave]

I don't think 3 different carbs are all going to have floats that are off at the same time. Have you checked all vacuum lines for leaks? Has the idle been checked or adjusted with the car in drive? What sounds good in park,may be to low in gear. Good luck!

[68C15]

carb with a vac. leak will be low and rough idle.
injection (with an IAC) having a vacuum leak will have a high idle.
I cant remember for sure but is the 1982 Qjet a feedback model with the MC solenoid? (ie. computer controlled timing etc.)

[Kager67]

My 78 blazer did the same thing. It was the T fitting on the rear of the intake. I replaced the rubber hose going to the trans. and now it works perfect. Just something to check.


Kager

[fastwillie 696969]

check for vuccum leaks at the intake manifold with some propane

[Sillyoldman]

Originally Posted by 70blowngmc

check for vuccum leaks at the intake manifold with some propane

Never heard of that. How do you do it? Sounds interesting. Since propane drops do you release propane over the intake and watch to see it it sucks in?

[fastwillie 696969]

Originally Posted by Sillyoldman

Never heard of that. How do you do it? Sounds interesting. Since propane drops do you release propane over the intake and watch to see it it sucks in?

hey sillyoldman its a old trick i learned from a ford mechanic back in the 80s ,proper way to check for vaccum leaks
get a bottle of propane and rubber hose on the tip like a welders tip just start the car and turn on the propane start checking for leaks when i idle picks up you know where your leak is at
dont use brake cleaner or carb cleaner for checking leaks
you spray around the dizzy it might get spark from the points and
poof your on fire

[Hoods69BadBowTie]

I am thinking a vacuum leak somewhere might be causing it.

[chevymad]

This is going to sound wierd. But I had the same problem with my 87 formula. I'd just finished painting it, then went to pull it out of the barn and everytime I put it in gear it died. Seemed to run fine in neutral though. Looked at everything couldnt find anything wrong. What it finally ended up being was the ignition pickup. Corrosion had eaten it up and it was trying to unwind.

[70rs/ss]

Won't propane.....POOOF too?!! For sure sounds like a vac leak, maybe the brake booster line, since you put the brake on when in D or R which would allow it to run in P but open a big leak in D or R?

[fastwillie 696969]

yeah the diaphram could be leaking in the booster itself ,check to see if the booster is working properly by
pumping the brakes up and hold them then start the car and see if the pedal drops towards the floor if it does booster is good