In order to trouble shoot erractic idle/take off issues, I need help with vaccum line routing and vaccum measurements.
I just bought this 84' Trans Am 305 "H" for a "symbolic" price as the previous owner was told that it needs a new engine. It sounds VERY healthy, it is very stable at WOT and the car is generaly in near "mint" condition. My plan is to restore it to original factory condition.

Status:
Rebuilt M4ME carburator (original)
New plugs, filters, EGR, PCV etc.
New O-sensor, the EGR solenoid valve "clicks" and changes vaccum throughput w/RPM change, TPS measures changes, M/C also, I have not yet tested O-sensor, MAP-sensor or other sensors for output.
Closed loop kicks in after 30 sec.

Here is the problem:
Idle is erractic and unstable.
Much hesitation until warm (150F), where hesitation is less.
"check engine" (code 32) durring deceleration. Goes out after 10-15 sec. at idle, cruise or acceleration.
Hard to drive durring take-off and low/medium throttle.

Remedy status:
Have tried to check all vaccum connections, but I cannot get a direct/ported flow diagram.
Not a lot of vaccum at "where I think" the vaccum hose for the EGR solenoid should be connected (bottom R-F on carb).
When I got the car the MAP sensor hose was connected to "the engine compartment light switch", witch leads me to believe that other hoses may be wrongly connected as well.
A "high end" shop told me today that the engine has "internal" problems, but when I asked what kind and where I only got an answer that I should "get a new engine".

I did over 130 MPH in dense traffic on the freeway today. I DO NOT need a new engine.

Help!

 

Welcome to TGO!

You're new, so I'll break you in slowly

Click the search button, top right hand of the screen. <A HREF="https://www.thirdgen.org/techbb2/search.php?s=">HERE'S A LINK</A> in case you miss it. When promted for the text, put in "LG4 vacuum diagram." Click the very first topic that shows up. There is a diagram there. That's "Search 101."

Vin "H" you refer to is the LG4 engine, carbureted 305.

How do you know you were goint 130+? Did you do the tire size, rpm, trans ratio, and gear ratio equation?

 

I've posted a copy of a sticker from a L69 numerous times, including one just the other day; a quick search should find it. It's basically identical to yours except for the appearance of the air cleaner on the drawing.

Check every line carefully for cracks etc. as well as mis-connections. They're probably old and brittle and ready to turn to dust.

There will be little or no vacuum at the port that serves the EGR at idle. It only has vacuum at higher throttle openings.

 

Thanks guys.

I still dont have the measurement values for the individual vacuum connections.
Is it possible that the problem is caused by "gunk" buildup in the intake manifold?

I will return with compression numbers and more.


SPEED!
I passed my partner when he did 120MPH in his "tricked out" 911 when he did 125MPH. I know, we are kinda crazy here.
I tested his 911 with my calibrated KZ1100.

 

Maybe this will help in the future (FAQ forum).

https://www.thirdgen.org/techbb2/sho...hreadid=257699

130 MPH in a stock LG4 -

130 KPH in a stock LG4 - :nono: