85 cutlass 442 carb problems

[ganon2234]

hi folks!
ive had this 85 cutlass 442 for almost 2 years now, and my dad used it as a daily driver for a few years before that.
this past summer (chicago burbs) when there would be a SUPER humid day, particularly after rain. starting the car and driving for a few minutes it would suddenly start bucking like an animal. the throttle would immediately cut off completely and to fix it i would have to let go of gas, and reapply gas, or completely floor it. the car would then run horribly, like it was on 6 cyl instead of 8. and the only way to get it to run DECENT, would be an appropriate speed (55+ in overdrive) 30+ in drive. etc. it took me a while to realize i could nurse it along if i ran it through the gears instead of leaving it in overdrive. this is very scary, driving down roads with the engine throttle being very radical. also there would be noises like its hopping off the engine mounts or a rod is being thrown! at a stoplight i have to keep gas pedal on a bit, or drop it in neutral and give it some gas so it wont die. so if i am able, i would stop in a parking lot for 7 minutes, killing the engine. after a restart it would be perfectly fine.
this happened a handful of times in the summer on super humid days after a rain.

however it just happened again last sunday, in the dead of winter. i might have only let the car warmup a few minutes, and as soon as i start doing some city driving (20-30 mph) its doing these same insane things. i stopped in a parking lot for a few mins to see if that would fix it. it did fix it, even though the car ran and accelerated good, it seemed like it was very tired and the engine wasnt running as smooth as it had the past year. after driving it relatively fine for 40 mins i sit at a stoplight, then after taking off it starts running crappy, bogging down, radical throttle etc. now it has been in poor shape this whole week 🙁

ive been considering buying a carb off my neighbor, or one online with a lifetime warranty.
v8 307 olds 442. 4 bbl carb. auto trans.

 

[axisg]

so what makes you think its the carb ? Sounds to me like you need a full tuneup

 

[87ttop]

sounds like full tune up and carb adjustment

 

[ganon2234]

there is a vacuum leak somewhere. when the car is idling and i use a finger to almost close the small air intake on the carb, it actually increases in idle speed, ( it does choke out if i close it completely though.
recently i did use a carburator repair kit on it. mostly new gaskets and the gas needle thing, and a few other parts were with it.
i cant tell if it has helped or not.

i dont know what a full tune up means aside from taking it somewhere to get a pressure check on each cylinder, and adjusting the timing.

 

[88hurstolds]

Sounds like the EGR solinoid or a bad EGR or stuck EFE valve (heat riser).
Also moisture could be getting in the distributor and frying out the ignition module.
The distributor advance is controlled by the computer and adjusts according to O2, temp and driving speed as well as throttle position (TPS).
Doesn't hurt to change all the vacuum lines, EGR, cap, roter, plugs and wires. Believe it or not the distributor can corrode from sitting even though there are very few miles on it.

 

[Blake442]

It's natures way of telling you that you shouldn't be driving a 442 in the winter... :lol:

 

[RITTER]

Sounds like the EGR solinoid or a bad EGR or stuck EFE valve (heat riser).
Also moisture could be getting in the distributor and frying out the ignition module.
The distributor advance is controlled by the computer and adjusts according to O2, temp and driving speed as well as throttle position (TPS).
Doesn't hurt to change all the vacuum lines, EGR, cap, roter, plugs and wires. Believe it or not the distributor can corrode from sitting even though there are very few miles on it.

x2

 

[ganon2234]

your description of the distrobutor advance is a little intimidating. about a year ago i put headers on the car and theres been o2 related throttle or idle "problems" or almost problems, since then. whenever i go over 50 i get a check engine light, probably cause of the o2. i dont know how to disable that. i remember asking and reading about this a while ago here, but dont remember the answer. i think we re-put the o2 sensor in the header, but its not getting the same o2 as original because its duals, not all in one collector like stock.....
..
will update more when i check into these things

 

[AlanB]

when the car is idling and i use a finger to almost close the small air intake on the carb, it actually increases in idle speed, ( it does choke out if i close it completely though.

your description of the distrobutor advance is a little intimidating. about a year ago i put headers on the car and theres been o2 related throttle or idle "problems" or almost problems, since then. whenever i go over 50 i get a check engine light, probably cause of the o2. i dont know how to disable that. i remember asking and reading about this a while ago here, but dont remember the answer.

So you have a lean condition at idle, and you're setting a code driving down the road. I would start chasing down both of those problems. What is the code? It could be a big clue to your problem. You shouldn't disable the code, you should find out why it is being set and address the problem.

Did this problem start after you did the carb?

 

[HarryOlds86]

Like said before... start with a good tune-up....... plugs, wires, distributor cap, rotor, fuel filter. Usualy "bucking" is an ignition problem. the knocking noise you described could be caused by an ignition cross fire (spark jumping to the wrong cylinder). Also your fuel filter could be clogged causing a lean condition. If it runs better after it sits for a minute or so, thats the time it takes for the fuel to seep through the filter. Just be careful not to cross thread the filter housing into the carb and make sure the little plastic gasket is in good shape.