So I found out today July 29th 2012, that my car has NOT been on the road since 2003. Iv only owned few months!!!
Looked and ran like crap when I got it.
it's the 86 t/a Lg4 carb 700r4 auto trans 150k
What iv done so far... Replaced fuel pump (on motor) not in tank! Replaced air filter,fuel filter, plugs,wires, rotor, cap. Iv had timed 6* advanced. NSS, starter, battery, cables, 2 1/2 cat back exhaust, magna flo cat. (stock y and manifolds)
New 180 thermostat and coolant hoses. Replaced all vac lines..

Car was running pretty good or I thought until I floored it for first time of the line (red light) it bogged to about 1,300 Rpms were it stayed for about 5 seconds. I had to let off gas and and feather it to not stall out in traffic. Since then it runs rough in drive even low cruise speeds.

What iv read from the forums was this.
1. Accelerator pump - yes I get a strong squirt of fuel both sides.
2. AV tension - iv adjusted it in 1/8 turns, starting from "0" tension. Didn't help. So I left it set at "0".
3. Timing - I had the car timed at a shop set to 6* advance. And double checked after.
4. Tuneup- Wires,plugs,cap,rotor, fuel,oil,air filters all new.
5. Choke - choke pull off. Sucks down instant start. Pulled vac line and blocked it off it went back down and stayed (till unblocked)
6. Vacuum - replaced all vacuum lines.

What might I be missing. Sorry for the long post!!! I would love to be out on the road with the rest of the third gens enjoying it. Instead of in the driveway under the hood all the time..
Iv read that there is a pump "in tank" too. Could that be my prob?

 

1. How accurate is the timing mark? You don't know, you say? Then how accurate do you suppose all this "6°" stuff is? Set the timing to where the car runs the best. Don't outsmart yourself over some "number". "If it RUNS good, it IS good".

2. AV tension should be around 7/8 turn for a 305. It'll have a MAJOR lean-out if it's much lower than that.

3. If it runs rough, doesn't matter how recently the plugs were put in. You have a cyl not firing. Pull em out and look at em. Check the wires carefully while you're at it.

4. You didn't say where you adusted the rockers to.

 

From lining up the timing mark to 0 then advancing to 6. Runs better at 6. But not great!
I moved the AV tension to 7/8 and little change. I did NOT change/set any rockers..
Tommorow I will pull the plugs and check them out.

 

Took out spark plugs. All were very carbon covered. My number 4 cyl was wet with gas

 

Replaced plugs. Runs smooth. But now it's over heating. I'm pretty sure it's my T-stat. The upper radiator hose stays solid. No flow through thermostat..

 

I always boil a new thermostat on the stove to ensure it works. I have had way to many new failures over the years to chance it.

 

Timing being off can also cause a car to overheat. Are your fan/fans running? Still have the air dam under car?