So I'm having some issues with my 84 GS automatic. Theres a couple of issues I'm experiencing, but they may be related.

First up, some specs on what Ive done to the car. It's got about 150 miles on the rebuild, new air filter, timed up, leaned out the idle properly thanks to Sterlings little write up, I've got new spark plugs and fuel filter to put it. The car sat for a winter in storage, with stabil in the fuel. Oil pressure good, temp good, alternator good, fuel status unknown, vacuum lines appear to all be hooked up. I also have a cat delete pipe, and the stock muffler.

So heres my issue. The car (in park or neutral) idles roughly at 1500rpm. Sometimes it idles consistently, sometimes it sputters and the rpm drops about 200 rpm, to 1300rpm. After a LOT of warming up, when i put the car into reverse or drive, the rpm drops to about 750-800rpm, and the car will run and drive like normal, no sputtering, no hesitations, no nothing.

However, sometimes it feels like the car is getting bad gas. Every once in a while the car gets the rougher idle (after being fully warmed up and driven for a while) and will die if i put it into gear.

It feels as though if the car is idling at anything under 1500rpm, it will die if i put it in gear. And it also feels like I've got bad gas based on how at random intervals the car will run roughly.

Last night things got a little strange when i was at the gas station, putting some mroe gas in to try to help get rid of the bad gas possibility, and when i went to start the car, it fired up, idled really rough, put it in gear, and it died. When to start it again and it would not start at all. Only way it would fire was if my buddy kept firing starter fluid into the carb. It would burn the starter fluid and then just die right away, like it wasn't getting gas.

Eventually, the car did start and i pegged it at 3k rpm for a couple minutes to try to clean it out and get it running steady. I put it in gear, it didn't die, so i said to hell with legality and hauled *** to get the girl home in one piece.

So i feel like maybe the plugs are getting worn out or the fuel filter is clogged up, so I'm going to replace them both today, but I was wondering if anyone else knew anything that I should check over.

 

Those would be the first two I'd look at; fuel filter, more then plugs.

Check the fuel level in the carb by looking at the sight glasses front and rear (rear needs a mirror, flashlight, and practice to see easily); fuel level should be at/near the middle of the window both prior to starting, while cranking, and while running. Gotta check both.

The "starter fluid" thing sounds like fuel starvation. Did you get a strong smell of gas from the tailpipe while cranking WOT but not starting? If not, probably fuel starvation.

Seeing the rear sight glass (fuel level shown is high; should be at the "notch" you see at the side of the window) with a mirror:



Holding the mirror right in front of the right-side heater hose that comes out of the firewall seems to work best.

 

No it didnt smell flooded but it was hard to tell since i was stuck at the gas pump just after filling up the tank.

I was thinking maybe its a vacuum leak causing the idle issues, but i can get it to idle around 750rpms easily, just if i put it in gear when its idling that low, it dies or idles at 0rpm (gauge reading)

 

it could totally be bad gas/clogged filter...

try richening up the idle mixture a little, and see if the stumbles get better. if the gas is bad, it'll want to be richer.

 

Do you think that could be the source of the high idle problem as well?

 

High idle is generally the result of:
Too lean mix/improper idle air mix setting
Over tight throttle cable holding throttle open a bit
Vacuum leak
(rare) fuel starvation right at the edge of what's needed to idle.

The fact that your car will start on starting fluid rules out ignition pretty clearly. Somehow you don't seem to be getting enough fuel for the airflow. Could be too much air (idle setting/vacuum leak) or fuel starvation (idle setting/clogged line/failing pump/plugged carb jet/plugged tank pickup etc)

Looking at your overall post, it sounds like it's something that is coming and going and may be related to heat, but it may have been getting worse over time. Could be bad/wet gas but it's have to be really bad to give the symptoms you describe.

So, start simple & work up. Making sure enough gas is getting to the carb is step # 1:
Bowl level check
Fuel pressure check
Fuel volume check

Everything else depends on that.

Oh, and is your choke working?

 

Choke works just fine.

I checked some more things out as well. So far I've replaced the spark plugs, and tinkered with the idle tune/speed a bit more, it seems to be getting a bit better. Fuel filter is next on the list but I have to wait for another set of hands to help me as to not lose my full tank of gas. Fuel levels in the bowls are dead on where they should be as well. I watched the jets while it was idling as well, they were basically dribbling, idling at 900rpm at the time. So i know it is getting gas but i may shoot some carb cleaner through just to be safe there.

Would you guys recommend putting some heet in the tank? I've heard that can fix a bad tank of gas.

 

Heet or other fuel drier wouldn't hurt.

 

Well looks like the gas is fine more than likely. Got the new fuel filter in as well, wasn't the problem, so I went back to tuning. Looks like you were dead on. It was too lean from the looks of it. However, before i got to figure it out completely, the fuel pump went boom. I'll be getting one of those tomorrow (non-OEM) and hopefully end all my problems