Bucking while cruising

[RangerJoe]

I've had my car out 4 or 5 times in the past two weeks. On two occasions, when weather was cold (once about 35 degrees and other time about 55 degrees), my car wants to buck while cruising. It has always bucked at low rpm because of the cam, but usually once I am around 2000rpm it clears up. It seems to be doing it at 2000+ right now. This is only a slight throttle, when I am wide open it drives fine. It also idles fine. The car is also up to operating temp while this is going on.

I searched through Google and found a few issues that might be relevant. One post described my problem as having a heavy trailer behind your truck and it is always pushing or pulling the truck. It is kinda like that. Some post suggest that it could be the ECT or ACT, another suggested the TPS.

I have checked the codes and I am fine there. The TPS was replaced about 6 months ago, I haven't had a chance to check the voltage yet, but I don't believe it is the TPS. Another post I found mentioned too much timing. I think this may be where my problem is. I run 16 degrees with the spout out. That has been fine in over the summer time, but could this be my issue now? Do I need to back it down to 14 degrees or less?

Thanks for any help!
Joe

 

[Gearbanger 101]

Two things. First, it sounds like your timing might be a little too far advanced. Try backing it off a degree or two and see if it goes away. Barring that, when was the last time the car had a tune up. Bad plugs/wires will create a bit of a miss under light throttle.

 

[RangerJoe]

Plugs have 3000 miles on them, they are gapped to .045. Wires are FRPP and about two years old...could probably use replacing. Stock distributor with MSD rotor and cap, 3000 miles on them, MSD coil that was put on when wires were and MSD 6AL (yeah, yeah, I know).

Now that the suns up and I won't wake the neighbors, I'm going to retard my timing a bit and see if that helps.

Thanks,
Joe

 

[junkyardwarrior]

I have the same problem with mine, along with another problem (idle surge). No vacuum leaks. Retarding the timing helps but I can retard it all the way back to 2 ATDC and it still does it...of course then it has zero power, runs like poo and the exhaust gets super hot.

Going to watch this thread. If I can figure mine out, I'll definitely offer my experience.

 

[RangerJoe]

I have the same problem with mine, along with another problem (idle surge). No vacuum leaks. Retarding the timing helps but I can retard it all the way back to 2 ATDC and it still does it...of course then it has zero power, runs like poo and the exhaust gets super hot.

Going to watch this thread. If I can figure mine out, I'll definitely offer my experience.

Mine doesn't surge, it normally runs fine and its not surging now. Just to update, I checked my TPS and it was good, .98-.99. I then retarded my timing to 14 degrees. I drove it last night in about 45-50 degree weather. It drove fine. I will keep watching it, but I think I had too much timing in it. I ran it at 14 degrees for a long time and just bumped it up to 16 degrees towards the end of summer. Looks like it was just too much.

If I were you I would look for the "idle surge checklist" and try going through it. You will probably find your problem in there somewhere. If anything changes on my end I will let you know.

Joe