This is on my 78 Sedan, 2.3l motor 4spd transmission.
So I have this strange pulsing/jerking motion while accelerating. No abnormal noise from the clutch though, which was my first guess.
It started after I removed the snow tires and put regular tires on the car. At the same time, I adjusted the clutch cable and used carb cleaner to clean out the throttle bores on the carburetor. I have since had the flywheel resurfaced and installed a new clutch last week and it is still doing it.
Tonight I changed the spark plugs out for new ones and it barely helped.
Could it be the wheels for my regular tires are out of balanced or thrown a weight?
poor adjustment on the clutch? Did you mess with the timing? May have clogged something when you soaked the carb
I don't think anything was clogged while cleaning the carb. I normally clean it up that way every three months.
I suppose it could be the clutch adjustment. I will try adjusting it again Friday. My 78 has a mustang 2 clutch cable setup with the adjustment tube on the firewall. I installed that three years ago and never had an issue, but it is worth looking into I suppose.
Well I stopped by my parents today and while there I decided to take advantage of the garage and the jack.
I adjusted the clutch cable so there is 1/8" of space between the release bearing and the pressure plate "spring". I also checked the wheel bearings. Tightened them up while spinning the rotor, then backed them off loose, then tightened them snug.
It's still pulsing a bit though.....
I did notice the right side caliper is sticking. The rotor won't rotate without some good effort. This is frustrating since I just replaced both calipers right before winter started! At least they are under a lifetime warranty, but it's finding someone to help me bleed the brakes that is the hard part!
I'm wondering if this is part of the pulsing, but I would think that even with a sticky caliper, I would notice it upon a free rolling deceleration in neutral as well, which I don't.
Since the issue became present after removing the snow tires and adjusting the clutch, and I have a brand new clutch and resurfaced flywheel in the car now, I'm leaning towards unbalanced tires/wheels and a possibly alignment.
Your pulsing may be going in time with the rotor that is now warped due to the sticky caliper. sucks, but it could be a lot worse.
I should be able to get the rotors resurfaced if they are not warped to badly. I bought them new about three years ago and have never had them resurfaced. If I do need a new rotor, I have a place locally which sells them for $58 each.
www.fastundercar.com
I think I got it figured out. I replaced the spark plug wires, cap and rotor today. I did the spark plugs on Sunday. It was idling really rough today which gave me the idea to change out the ignition stuff today. I took it for a test drive around the block after letting it warm up, seems good so far. I will know more when I get the chance to drive it farther.
If this isn't it, there are two other possibilities...
As stated, the passenger side caliper is sticking which is more likely than the hole I have in the exhaust pipe at the rear most hanger, but is it even possible for an exhaust leak to cause pulsing on a pre-computer controlled emissions car?
also...
If mashing the gas to the floor and it runs better (but temporarily), then it is running too lean.
If doing so makes it worse, it is running rich. I had that issue when the alt brushed wore out and the choke closed up.
I will keep this in mind 78txpony!
I think I may have figured it out tonight. With the local big car show coming up that I will be attending, this weekend, I decided to tackle it before making the 30 mile trip out to Emmett.
I pulled the carburetor apart and cleaned everything really well, using lots of carb cleaner and towels to remove varnish. I also disassembled the separator/EGR plate and cleaned it really well, then cleaned what I could of the inside of the intake manifold, and as far into the runners as I could. Finally cleaning the PCV valve as well. I put it all back together and readjusted the float and replaced the fuel filter. After the carb was done I started the car with the distributor hold down loosened slightly and readjusted the timing a degree or two (it was slightly off).
Runs silky smooth again! :D :D