Still Bucking

[Flw Sock]

I posted a little while ago about my car bucking at low speeds. I never found the reason for it, and it's even worse now. I replaced the TPS sensor, and it didn't help. If anything, it made it worse. I unplugged it and drove it around the block to see if that was the problem, but it still bucks even when it's not connected. I took it to a reputable mechanic who I've gone to for years; and is a very trusted family friend. He drove it and thinks it has play in the tranny; but I have to disagree. The engine RPMs go down when I try to take off and when the bucking starts. This car is impossible to drive in traffic and I'm sick of burning the crap out of my clutch to try to take off in first or second gear. Sometimes I even have to start in 3rd gear and floor it to not buck. If I floor the car it will violently jerk once but then be ok. If I don't floor it at low speeds, it violently jerks and is horrible to drive until you get to 25+mph. All of the motor mounts check out, and as I said before the TPS is brand new.

Please help.

[ryanprins13]

Im lazy, could you post a link to the other thread here?
Crank position sensor is dirty! Check it.
How is your battery and alternater doing? 14 volts at idle?
Does the car idle well? Any misfire? Low on power?
I presume its efi, have you checked the intake tubing for cracks or leaks? They like to crack on the bottom of the flex joint near the filter so that you actually have to remove the hose to check it. These cars do funny things with vaccume leaks or a messed vaf.
When did you change your fuel filter last? Recent tune ups like spark plugs, cap and rotor? Coil?


Sent from my iPhone using Tapatalk

[TominMO]

You might also test the TPS, to see if it is actually functioning properly.

[WmWatt]

Do you have what's called "clutch chatter"? I get that under certain atmospheric conditions. I've read it can be caused by moisture or glazing on the clutch surface or perhaps both. If I give it more gas when pulling away that can stop it but usually I just pull away slowly not to put too much stess on it and that helps too. I've read here that other Festiva owners have it. It's too much trouble and expense to put in a new clutch.

[mikemounlio]

Check you dissy cap. I have have a bad cap right now and when i take off its like it loses power for a second then back on giving a buck kinda. I took the cap off the other day and cleaned it all out. Used some light sand paper on the metal parts and put it back together thinking i was gonna head to the parts store to pick a new one up. Nope car runs great for a short time then starts to buck again. The cap is cheap its just no time to change the thing.

[Flw Sock]

There's no clutch chatter. The transmission itself shows no signs that anything is wrong. I'll have a look at the dizzy cap before work today, because when it bucks it does lose power sometimes, and even at speed sometimes it loses power for a second or two. Both the battery and alternator are brain new. The car idles fine. The plugs and wires are newer. I'll check the intake for cracks.

[mikemounlio]

Sounds like a bad cap to me. Mine does the same thing. Mine happens at random times. Most of the time when i hit the gas itll die out then jump back to life and take off. After i clean the cap up boom runs like it should. Good luck. Post back and let us know

[Flw Sock]

I checked the cap and rotor. Both had a little bit of corrosion. I cleaned it off with no improvement whatsoever. I also tried readjusting the TPS sensor itself, also with no change. However! I did notice something. When the car is running and I put some weight directly on the intake manifold, the car's RPM goes down significantly, if I put a little more pressure and hold it for a couple seconds the car will die. I think this could be the problem, because under even slight acceleration, the engine would rock back a little bit (the same direction that I would push in; down and slightly towards the firewall). I couldn't find any kinked hoses or anything. Any ideas as to what this could be?

[william]

Uper to low intake gasket?

[mikemounlio]

With car at idle hit the area in question with a can of starter fluid. If the motor revs up you have a leak that needs to be fixed.

[SiliconSoul]

https://www.youtube.com/watch?v=zMok2y05jNE&app=desktop

How to find vacuum leaks with a cigar...

[ryanprins13]

With car at idle hit the area in question with a can of starter fluid. If the motor revs up you have a leak that needs to be fixed.

Now that is a good idea i never thought of!


Sent from my iPhone using Tapatalk

[canada rocket]

I had a Festiva that would buck when I was taking off. I checked lots of things but nothing seemed to help. I brought it to a shop I trusted and they came up with nothing. I found out that the rubber air filter duct that ran from the air filter to the engine was cracked in the accordion part. I taped it up with duct tape and the car ran fine after that. It's a simple fix that cost practically nothing. Always check that duct.

[mikemounlio]

use the can of starter fluid 1st. Its a couple bucks and will find any leaks. its easy point shot listen

[jimdigs]

This probably isn't it but I'm gonna throw it out there anyway. My car bucks and hiccups when I get near a 1/4 tank of gas and that is because I have a rusty fuel tanks and the fuel pump sock gets all dirty on the bottom with rust and the gas will not flow correctly and my car will do exactly what you are describing. But yours sounds like it does it all the time, maybe a real dirty fuel pump sock? Just thought I'd throw that at ya.