Joffroi

I have an issue with my 68 Cutlass and want help trying to figure out what might be the issue.

I have a 350, 3 speed auto transmission, 4bbl edelbrock carb. Originally, I thought my transmission was slipping and maybe needed a rebuild. Took it to the shop, they said it looked fine and it was just a tube that was disconnected. They replaced the tube for free, drove it and said it shifted great. They said I needed to just drive it more and keep track of fluids.

I was ecstatic, drove it and it appeared to shift great.

In the next days, I drove it on and off, "nicely" and "aggressively". There was still an issue.

It seemed when I would floor it (either at a stop or on the interstate), the engine would rev and go back and forth between 3500rpms and 4000rpms in half second intervals and do this as long as I had the pedal down. It would not do this every time, but did seem to do this more when the engine was hot.

Transmission issue? Carb issues? Gas line issue?

I'm not sure, any help would be great. Let me know if I can provide more information to help diagnose this.

f-85

Sounds like your kickdown cable is adjusted alittle to tight. Try setting it just alittle looser and that should fix your problem. No major issue. It should be an easy fix.

Joffroi

Where is it? Anyone happen to have a picture of what I need to look for . I'm happy this should be an easy fix. Learning something new everyday.

f-85

If you have a th350 trans it will have a kickdown cable that helps control shiftpoints. Assuming you have a 350 trans (thats what would have came with the 350 engine from he factory)



Its a cable that comes from the trans to the throttle linkage. It will be right below your throttle cable. There should be a button on the cable right where it attaches to the bracket at the carb. I bet it is set all the way tight or close to it. How i adjust it is ill hold the throttle wide open and with one finger pull up on the wire coming out of the cable. Now becarful because it the cable is spring loaded. Push the button and let the cable come out just alittle to give it just alittle more slack. Then just go take it for a test spin and see if that solve your problem. You can go back and forth trying different tension setting with it to get your desired shift points.

Joffroi

Sounds good, I'll see if I can find all that after work today. Hopefully it does the trick. Thanks

hookem horns

I have a very similar setup in my 69 cutlass and also need to loosen the kickdown a little. The description above is true only if the cable was rerouted to the aftermarket carb (pretty common). Original connection was at the gas pedal - cable for the TH350 and electric for the Jetaway (TH400 too, I think).

hookem horns

Assuming trans is a TH350, can also simply disconnect the kickdown cable at the carb/pedal to see if there is a difference. Won't have a "passing gear" is all.

Rickman48

I'd check the fuel filter - the one at the carb end of the gas line first, then float level in the carb, then fuel pump pressure.
Acceleration could cause the fuel problems, and still run good at cruise.

Joffroi

I just wanted to double check with you. Is this what I need to tighten?
UUfAf.jpg

Looks like I might need to replace the throttle cable soon too.

f-85

Yes thats the kickdown cable. But if your trans is shifting up and down at points its to tight. So try loosening it slightly.

Joffroi

Great, I'll try to loosen it when I get time. In-laws just came into town :-/.haha

jag1886

Sooner not later, that things had it.