Surging idle on cold start

[K-Man]

your air cleaner doesn't have the flapper schurkey is talking about?
i assume you plugged any vac lines if needed.
Thinger says his 94 doesn't have the flapper, just the tube from the exhaust manifold, my 95 has both.
if it ever stops raining i'll take a pic and test mine.

It does have the flapper and the dryer vent tube.

 

[K-Man]

A picture would be good. I have trouble imagining that GM would put a heat stove and hose on the air cleaner...and NOT install a flapper.

But unlike the older ones, the GMT400/TBI flappers are not vacuum-operated. They've got a wax lump inside a mechanism, similar to the coolant thermostat. When the wax is cold, the flapper allows hot air into the snorkel. When it gets hot and expands, it shuts off the hot air. In-between, it's regulating the air temp inside the air cleaner.

And the whole thing is hidden, internal to the air cleaner.

Yes, it does have the flapper.

 

[PlayingWithTBI]

Is there a way to use that Tunerpro RT without buying an $80 usb?

Yes, you can use it with a $60 cable

OBD Diagnostics

aldlcable.com

 

[1997]

It does have the flapper and the dryer vent tube.

Then i wouldn't exepect it to run well cold without the aircleaner, flapper and warming tube to exhaust manifold.
That would apply to just removing the lid also.

is there a way you can confirm if the flapper is working correctly?
Mine moves freely, but will investigate its operation hopefully tomorrow, rains supposed to stop

 

[Erin]

Not to try & hijack but is the hose y’all are mentioning from the air duct to the manifold? Mine hasn’t had one since I got my truck.

 

[tayto]

get your injectors professionally cleaned.

is there play in your throttle shaft?

 

[1997]

Not to try & hijack but is the hose y’all are mentioning from the air duct to the manifold? Mine hasn’t had one since I got my truck.

yes, exhaust manifold to Air clearner snorkle, inside AC snorkle is a flapper like the old carbs used, they had a bimetal thermal spring.

I'll post a pic of mine when i can. picture worth 1000 words

 

[K-Man]

get your injectors professionally cleaned.

is there play in your throttle shaft?

I will check

 

[K-Man]

Then i wouldn't exepect it to run well cold without the aircleaner, flapper and warming tube to exhaust manifold.
That would apply to just removing the lid also.

is there a way you can confirm if the flapper is working correctly?
Mine moves freely, but will investigate its operation hopefully tomorrow, rains supposed to stop

Not to try & hijack but is the hose y’all are mentioning from the air duct to the manifold? Mine hasn’t had one since I got my truck.

Yes, it may help in the cold weather.

 

[Sabinoerc]

Is there a way to use that Tunerpro RT without buying an $80 usb?

I wondered same when I started and searched around, I think on gear head-ef, and found some guy explaining how to make your own for something like $10. But for me, the time to find the parts and then dealing my lousy electronics build/solder reliability when I’m already frustrated trying to fix something on the truck — it just wasn’t worth the time or aggravation. I bought a cable from Moates which also had pretty good how-instructions to get going.