Im not sure if this problem has been mentioned before, i think it has but to be safe ill post a new topic with my exact problem.

rite

i have a 1994 fait uno 999 fire.

i have a little problem with the engine acceleration.

the problem is my accelerator, when the car is out of gear (and in gear) i hold the accelerator down to rev the engine the accelerator revs fine. but when i hold the pedal steady bout 1/2way down or whatever and hold it the engine varies speed, like im moving the pedal but im not. this effects the driving of the car so when im accelerating the car pulls back like im easing off the pedal, you can see how this would annoy someone.

the engines varing speed appears to go up and down in a pattern, its not a random noise it happens the same distance apart, about a second between each rev dip.

if i hold the throttle cable tight from inside the engine the engine still fluctuates.

this problem has always been there so anything ive done to the car below hasnt fixed it

ive replaced the head gasket
throttle positioning sensor
general service. oil/water change filters changed. the usual

really really, if anyone has an idea fire them my way.
im not looking to spend a lot more money on it. so please if u suggest replacing a part give me the price aswell, if ya can.

That's difficult to diagnose - it could be a lot of things, but it might be worth getting an understanding of how the engine management works on your car.

I'll try and give some ideas (AIUI), but it can easily get very expensive with the bits and pieces involved.

A question first though - does it do this engine speed change only when the engine is cold (say in the first minute or two after starting), or only when warmed up, or at any operating temperature??

The reason for the question is to find out if it's an open loop, or closed loop problem: when warmed up, and working correctly, it should be closed loop.

Will waffle more, with further information

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Looks like your first item to think about is a filter you might have missed:
fuel filter

Failing that you might have a problem with the fuel pump, or muck in the tank around the pick-up pipe.

To find out more without spending much it might be worth taking the portion of the air-intake which covers the throttle body off, and looking down inside of the body.
If your UNO is how I imagine it to be it will be SPI, and the injector is on the top of the body.
You can see the fuel being injected - it might be possible to judge if the ammount of fuel is varying.

If it is varying, you've either got supply pressure problems (filter/pump as mentioned above), or the ECU may be altering the drive to the injector.
If it's not obviously varying - have you got any (not obvious) induction manifold, or pipe work, air leaks which are altering with engine movement??

See how you get on and post back.

the first thing i did was 2 replace the petrol filter. i should have mentioned that before. soz[^]

my car does have the throttle body where ya say, and it is single point injection. its 9.00pm were i am so ill have to wait till 2moro. but ill let ya know how it goes.

Hei.

Had the same problem. It still is there, but almost gone. Clean the air filter box - everything. Remove the breather hose that goes from the top of the engine into the filter box. There is a little metal filter in there. Push it out and clean it. Disconnect the fuel intake and return hoses. Make sure you have new clamps. (Is clamp the right word? I'm Norwegian...) Disconnect the electric wires. Unbolt the 4 screws that holds the unit (SPi injection unit) in place. Clean it. Reconnect everything. Remove the spark plugs, and use a bit of sandpaper (right word? again...) on the bottom to reveal the good old spark plug. Screw in the spark plug. Don't use too much torque. Turn the ignition... Tadaaa.

Well, it worked for me. The engine ran more smoothly than ever. It's worth a try. My Uno is also from 1994, but I've got a much bigger engine: The 1.1i.e.S. Oh-yee.

Morten.

Excellant post, Morten.
Nice to have the words from someone who's been there and done that

excursion_uk - would you keep us up to date with the progress, please??

Ill get right on it, sorry would have done it today but work has been rite up my ass trying to get deadlines met ya know how it is leaving s**t to the last minute, figgered i would have grown outta that.

im of 2moro so ill do it then post back tomoro evening
big thanx to all thats helped

The problem is solved, thanx to all that helped. running real smooth now.