My car had a wicked bad case of parking lot bucking. Whenever I tried to feather the throttle at parking lot speeds, the car would lurch significantly. Lifting off the throttle would throw me forward as compression breaking slowed the car. As soon as I would just touch the throttle again I’d get thrown back in my seat as the car accelerated. I got in the habit of slipping the clutch and getting some speed up, then pushing the clutch in and coasting until I needed some more gas. It was a major pain in the a$$. Getting stuck in traffic flowing less than 20MPH was a nightmare.
I think part of what was happening was caused by the ECU. This car is known for not being real smooth at parking lot speeds. The ECU cuts fuel as you lift (for economy and emissions) and then adds fuel back as you touch the throttle again. I think this was only part of my problem.
Some time ago, I noticed a slight improvement after adding a can of a fuel system cleaner. I waited until it was almost time for an oil change, and then went through three tanks of gas in a row with various cleaners. I think I used Redline once, Techron once, and something else I can’t remember right now. This made a significant improvement.
Between that oil change and my most recent, I used some of the maintenance level products, like Fuel Power, Lucas UCL and Redline at the maintenance dose. There wasn’t much improvement. I also ran a couple tanks at full dosage levels. Those tanks made improvements.
Before my most recent oil change, I did another run of two tanks with the cleaners. I also dribbled some Techron into the intake, like you would use Seafoam. Over a period of 12 to 18 months, I’ve probably run 8 to 10 tanks with full strength cleaners and about the same with maintenance does levels. It has been well worth it, as my car is significantly better. The bucking is still there a little bit, but if I am smooth on the throttle, it’s OK. Shifting is also better for some reason, and the car doesn’t bog as much off the line as I engage the clutch. There seems to be more power, the engine feels smoother, and according to my butt dyno, I have a lot more torque down low than before. I think there might even be more improvement to come.
I should also mention that regular Italian tune-ups help as well. If I hold the rev’s at 6,000 or so for a couple minutes, I notice an immediate improvement. This car sure likes revs!
So what was fixed? Just plain ‘ol carbon build up in the combustion chambers? I have never heard of CC deposits causing these symptoms. Deposits on the valves? I wonder if there might have been a big piece of junk in one of the injectors that has taken this long to dissolve. All tune-up and maintenance items are up to date. I had previously replaced a bunch of stuff trying to eliminate the problem, like the O2 sensor, MAF, caps & rotors (its dual plug), etc. I used Chevron gas (with Techron) until Shell V-Power came out, and now I use that. I don’t think I can blame the gas.
Any other ideas? Thanks in advance!
I think part of what was happening was caused by the ECU. This car is known for not being real smooth at parking lot speeds. The ECU cuts fuel as you lift (for economy and emissions) and then adds fuel back as you touch the throttle again. I think this was only part of my problem.
Some time ago, I noticed a slight improvement after adding a can of a fuel system cleaner. I waited until it was almost time for an oil change, and then went through three tanks of gas in a row with various cleaners. I think I used Redline once, Techron once, and something else I can’t remember right now. This made a significant improvement.
Between that oil change and my most recent, I used some of the maintenance level products, like Fuel Power, Lucas UCL and Redline at the maintenance dose. There wasn’t much improvement. I also ran a couple tanks at full dosage levels. Those tanks made improvements.
Before my most recent oil change, I did another run of two tanks with the cleaners. I also dribbled some Techron into the intake, like you would use Seafoam. Over a period of 12 to 18 months, I’ve probably run 8 to 10 tanks with full strength cleaners and about the same with maintenance does levels. It has been well worth it, as my car is significantly better. The bucking is still there a little bit, but if I am smooth on the throttle, it’s OK. Shifting is also better for some reason, and the car doesn’t bog as much off the line as I engage the clutch. There seems to be more power, the engine feels smoother, and according to my butt dyno, I have a lot more torque down low than before. I think there might even be more improvement to come.
I should also mention that regular Italian tune-ups help as well. If I hold the rev’s at 6,000 or so for a couple minutes, I notice an immediate improvement. This car sure likes revs!
So what was fixed? Just plain ‘ol carbon build up in the combustion chambers? I have never heard of CC deposits causing these symptoms. Deposits on the valves? I wonder if there might have been a big piece of junk in one of the injectors that has taken this long to dissolve. All tune-up and maintenance items are up to date. I had previously replaced a bunch of stuff trying to eliminate the problem, like the O2 sensor, MAF, caps & rotors (its dual plug), etc. I used Chevron gas (with Techron) until Shell V-Power came out, and now I use that. I don’t think I can blame the gas.
Any other ideas? Thanks in advance!
