Bucking

I have a 00 Accent and my problem is as followed, while driving it feels as though the motor is going in and out of limp mode. ill be cruising at about 2800 rpms and it will like loose power and as soon as it does it comes right back causeing a jerking or bucking feeling and every now and then a back fire pop in the exhaust just depending if i let off the gas when it happens or not, i do have a check engine light but never fails it goes off before i can make it to the parts store to get it read. it also does it sometimes when accelerating but hardly ever after you get the rpms up past 3500. now the things ive dont to try and fix this are, replaced the spark plugs, plug wires, and coil packs, i dont think it matters but u have also changed the water pump and thermostate, reason i dont think it matters is that it was doing it before i changed it. can someone please help the only other thing i can think it might be is the fuel pump.
Thanks in advance to anyone that can help!

Could the weather, snow, ice, rain, or a car wash play a factor in causing
''Limp mode'' ?

1) You need Air, Fuel, Ignition, and exhaust for horse power.
2) Look over service + parts records for clues.
3) New plugs, wires, and coil packs.
4) New air/fuel filters?
5) Clean MAF/IACT sensors with CRC MAF cleaner?
6) New upstream H02 sensors?

Doe's this car have a drive-by-wire system?

in the past year ive put a new crank sensor , iac , tps , maf , both O2's , plugs , wires , coil pack , thermostat , and water pump
problem started when i changed back to factory thermostat from a 170 degree one so the check engine light would stay off since the thermostat ive changed the water pump, plug, wires, and coils i even went back and put the 170 Degree thermostat back in just to check bad thing is i have poly urethane front and rear mounts and i went and filled the voids of a transmission mount with poly urethane so every little hiccup i feel and this bucking is driving me crazy. the other thing i thought about was maybe my trans i have the 5 speed manual and the diffarental is going bad again from where i slammed it (ive raised it back up some)

Hi evillow,
Sound like you are having a lot of fun. The backfire pop out the exhaust that you mention. This suggests you are not losing fuel at that time. For it to be so instantaneous like you describe i would be looking at the ignition side of things. You have changed many components so now it might be time to start checking the integrity of the circuits. The ECU relies on your crank sensor signal for crank speed and position, then triggers the primary circuit for the coils. I would be checking these two circuits. The only way to do this correctly is with a scope.

On the subject of codes stored, some codes can be stored for a sensor that may go out of range for an extended period, and a code reader would still retrieve those at a later date. But that won't happen if you have a primary drive fault on a vehicle of that age.

Since it is costing you in more ways than one, my advice is to find a good tech who knows what he is doing and it may save you time, money and frustration. With the correct tools and knowledge of the system he will have that fixed the first time it plays up.

I have a 2004 Accent that has the never ending check light. It was failing to accelerate and almost stalling. I took to dealership and they said it was the coils $247 and then talked me into changing belt, flushing the transmission and an oil change. His words were " you won't need any work for a long time" He said the check engine light was on and they (the Hyundai dealer ship) couldn't figure out what was wrong. I left the lot and 1/2 mile down the road then car did the bucking thing you descibe, literally snapping my neck forward. I called him the next day to tell him. I had to reschedule twice because of ice and snow. In the meantime, I had a mechanic laugh when I tried to get it inspected and told me it would never pass with a check engine light on. Yesterday, when I went back to the dealership, they told me that the transmission is FRIED and would cost $4000 but the car is worthless and not worth fixing and has a "whole raft of things wrong with it" and that somehow all this happened between the time I left and came back. 3 weeks. That they have no record of any transmission code and this is a new problem ( my problem, not theirs). I know nothing about cars and don't know if/ how to fight this. I spent 831 bucks at that place. They offered to sell me a new car and then found out I was a student with a tiny income and lost interest in me. I ended up crying to a complete stanger at a used car dealership and he said they had probably messed up my transmission with the flush. I'm sorry to hijack your post. This should be a new thread but I can't find how to do that and can't watch the darn video in the school library. I am sincerely hoping someone knows what to do. Can you put in a used transmission? I still have 2000 left to pay on this car. Also will the transmission go out in an instant? Could I die on I-35? or will it just slowly grind down until I am a turtle holding up traffic? I don't have anyone to ask. The first mechanic that I paid in cash, didn't change the belts and cracked a $300 oil cover and put a quart too much in. He told me it was my problem, too. I'm so tired of being ignorant and getting ripped off. I thought going to a dealership would end this. Help. please.

Yesterday, when I went back to the dealership, they told me that the transmission is FRIED Bucking is a strange description of a transmission symptom. I would get a second opinion. If you find a small solo operated workshop and explain your problem I am sure he would be happy to help you out. My suggestion would be to stay away from the dealer and find a workshop where the guy you talk to about the problem is the same guy that will be working on your vehicle. IF it was a tranny problem than a secondhand replacement should be about 1/3 of what you where quoted.


I thought going to a dealership would end this.
That's a :nono:
A dealership is only as good as the techs that they employ.

Give these guys a try if they are near you.

Colonial Auto Service
1705 Colt Cir, Marble Falls
830-798-9307

Ed's Tire and Auto Center
901 Industrial Blvd, Marble Falls
830-693-5331

A engine with poor deliverability, could give bad symptoms to a good transmission.
Focus on the engine's performance 1st.

it was the maf