Car sputters and bucks when accelerating
 

I have a 1998 Honda Civic DX Coupe, no mods, but one annoying problem. During normal acceleration the car starts sputtering and bucking so I have to gradually apply gas very slowly. I've also noticed that it doesn't do this or doesn't do it as bad, as when I first run the car when it is cold, perhaps the first 5 mins. I had a habit in the past of running the car when the gas light was on, which is virtually at empty, so maybe it is my fuel pump going bad. However, I still hear it pressurizing the fuel system when I turn the key to the On position. I need someone to confirm and have a diagnosis to the problem so I could replace parts myself and save me some money of going to a shop. Thanks!

Weak ignition is often the cause of this problem too. Do the standard tune-up if you haven't for a while: plugs, cap, rotor, wires.

Also change the fuel filter. Fuel flow can be checked by disconnecting the return hose (from the fuel pressure regulator to the pipe that goes back to the fuel tank). Loosen the gas cap first so there isn't pressure in the tank. After disconnecting the hose, direct it into a container and turn the key on but don't start the engine. During the priming period you should have a good flow of gas from the return hose.

I agree with mk's idea to start by checking and replacing basic components of the ignition system. After you have done this, then also check that the ignition timing is set to specification using a timing gun (see 96-98 Civic manual at the link in my signature).

A standard tuneup does not fix this problem, I have a 97 civic Ex Sedan 5 speed and it does the exact same thing. I did a complete tune-up gas filter also and the problem is still there, once the engine gets hot it starts bucking on acceleration. I would also like to find a fix for this problem so please help.

What exactly have you done thus far?

Is the CEL ON?

See if Ed Fisher's reply can maybe help you:

https://www.hondacivicforum.com/foru...hlight=stutter

I have been experiencing the same problem he had with my 99 Civic EX. I had the ignition coil and wires, new plugs, distributor cap and wires installed; still sputtered on accelleration. I filled up and took it back to my mechanic and the problem wasn't able to be duplicated. This leads me to believe you either: keep your tank above 1/2 a tank or you investigate the fuel pump for your problem. My mechanic said to bring it back for further diagnosis if the problem pops up again, but I generally keep over 1/2 tank of gas, so no telling if or when that might be.

Good point, LBKeith. I missed the potential link to low gas level. You guys should pull the fuel pump out and check whether the pump filter has come loose, as was the case for Ed Fisher's Civic.

All this time I never realized it only sputtered and bucked when the gas tank was 1/3 full. I filled my gas to full tank since it was the cheapest "fix" and the sputtering and bucking has gone away completely. I could almost conclude that the fuel pump pick-up screen is the culprit. Thanks for the responses guys. :):):)

Congrats on that fixxing the problem. Mine does exactly what yours was doing but I tried filling it to a full tank of gas and still having the same problems... Have another thread up for my problem tho so hopefully I can get it fixxed soon.

On a Toyota I had once there was a small crack in the air inlet plenum. The engine would rock slightly on the motor mounts on acceleration, open the crack just a little, allow unmetered air into the system, and cause a bucking. When the accelerator was released the engine would settle and idle perfectly. Pull on your plenums with the engine running and see if you can detect a crack or change in pitch. Just a thought, hope it helps.

Ed Fisher
Dallas, Tx