My '83 GS (near stock) has been acting up lately. It was fine a few weeks ago but lately, when driving back home from school (1 hour drive), I've noticed this started to happen.

My GS runs fine in the city and has no problems when redlining it through the lower gears and everything else feels fine. However, on the freeway, when in fifth gear and roughly 75-80mph (between 3500-4000rpm,) I started to get some bucking. One time, it got so bad that it kept bucking until it went down to 3000rpm's and got down to 60mph. This would happen when I'm going slightly uphill and trying to floor the gas a little more.

Tonight, when I drove it back on the highway. I couldn't accelerate past 4k RPM's and couldn't go faster than 80-85mph. It would start to buck badly, even more when it was under more of a load (going on slight uphills.)

What could be wrong? Is it my ignition? Is it my secondaries causing problems (even though it runs fine in the lower gears?) Fuel problem?

 

Check the fuel filter.

~T.J.

 

I agree with T.J.

 

Mine was doing that to when I bought it, but I never got around to fixxing it and it soon went away, in my opinion I dought its the filter but is worth a try, if that doesnt help try rebuilding the carb and adjusting the floats

 

I'm gonna go with fuel filter as well.. when i got my 12a, i was driving it home after buying it.. bucking like crazy, i was madder than hell, swapped filters and it all was great..

 

I change filters every 3000 miles, with the oil. they only cost a couple bucks with the plastic throw away kind. cured my problems.

 

yeah i'd say fuel filter too, if that doesn't fix it then it might be worth checking the fuel pump too

 

1000 bucks that its the fuel filter. i might even change mine this weekend

 

Start at the filter. If that doesnt work, move on. Pump, floats, carb cleaning, etc. Thats my advice, lol.

Oh, and before you ask, the reason it will still redline in the lower gears is because even though it may be consuming fuel at a fast rate from the float bowls, its not a high quantity because you run out of gear too fast. When you get on it in the higher gears, it consumes the fuel at a faster rate and higher quantity than what the float bowls are filling at (because the filter is slowing the fuel in the lines donw), therefor the car bucks and acts up like its running out of gas. Mine did the same things back in the day when I was new, and I couldnt imagine it being the fuel filter, but I changed it just because I remembered everyone babbling about it being the "wonder fix" and this that and the other thing. Ill be damned if it didnt fix it. Mine progressivly got worse from just accelerating in 5th gear to the point I couldnt even floor it up to 60 in 3rd without it cutting out on me. Swapped the filter and it was a beautiful thing.

~T.J.

 

My 2 revs...
Ihave a GSL-SE and mine was doing somethig very similar, except it did it in all gears when i would get above 4k rpm's. I ended up finding out that it was the catalytic converter. just food for thought. I'm sure that in your case it's probably the filter. best of luck.

 

I know that i wrote alot, but i may be helpful


catalytic onverters and fuel filters have similar warning signs, they both will make you bog down, but a cat that is going out wont cause a stumble like that...catalytic converter problems are most notable on accel, when you full throttle into it it feels like your running out of engine, you wont get full rpms or full power, and usually it will act like a rev limiter is on, but if you ease into the throttle you will think nothing is wrong (most of the time unless its a severe cat meltdown). fuel filters tend more to buck at cruising speeds, but then again with as old as our cars are, its Not wise to buy a cheap 5 dollar filter...with all the rust and contaminants in the fuel tank, you may do more harm than good by putting in a cheap filter that may not filter anything. also check your carb, my fuel bowl appears to be leaking and i belive that is where hard starts and bucking is coming from. also when your car is running take a can of carb cleaner and spray your vacuum lines down. if you notice a bog in rpms, you have some vacuum leaks to deal with as well that could cause the same problem...I work as a Tech for GM, and i figured maybe id go a little more in depth than the other guys about what could be wrong, just covering all the bases. hopefully its something easy and cheap though good luck

 

You guys rock!

Thanks for all the replies. I am going to start from the small things and work my way up until the problem is fixed so I'll be installing a new fuel filter this week. Will keep you guys updated.

 

I now everyone is saying its the filter, I'm not saying they're wrong its always a good Idea to change it often, but if it dosent help you should try at least cleaning out the carb, fuel companys are trying to save money so fuel isnt filtered as well and all the parefen wax can clog the jets

 

I have an 83LE and was having exactly the same problem. I changed the filter and began to use mmo after my fill ups and the problem went away.

 

I had this problem for several months after putting my 84 GSL back on the road after a year of sitting. The first thing I did was change the filter, which had some rusty water in it. But the problem came right back a day or two later, again the filter had some water but it wasn't clogged - you could blow through it easily. So another filter and a few hundred more miles and the problem comes back again. In the mean time I was was adding dry gas and I checked everything else in the fuel and electrical (swapped out plugs, wires, coils, igniters, fuel pump, etc) but nothing got rid of the high speed coughing and sputtering.

But putting in a new filter would get me a few days to a few weeks of trouble free driving. Now, 5 filters and 4000 miles later, it seems all the crap has come out of the tank and the problem is gone.

 

whats mmo

 

have u done a recent tune up on the car? that would be a good idea

 

Well, I changed the fuel filter the other day and just came back from a 50 mile trip. Overall, not even the slightest stumbling or bucking. I found the old fuel filter to be a little bit dirty too.

Also, the car seems to start easier too (or maybe its just the warmer weather.) Anyways, I'm happy that its running great again. I'll take it out on the freeway a few more times just to make sure.

Thanks again.