Technical Fiat punto mk2 1.8 problem

[essexHGT]

Fiat punto hgt 1.8 HGT 16V abarth. 188 2001 fly by wire

hello everyone my hgt has been playing up for ages, none knows what it can be so wondering if you can help me out..

car shakes on idling revs little by it self.struggles to start after been left for a while and you have to start the car and put your foot on the throttle to start it and it starts then dies again and try start it again it will struggle but will throttle all the way down the car starts but jumps.... when hot the car will start straight away.
when you left off the throttle the car has a delay in dropping rpm as meaning it still pulls at lower rpm for 1-2 seconds..
When i drive it sounds like a scooby (misfiring) then clears itself then does it again.. keep tapping on the throttle the rpm drop so low car nearly dies.
its basically holding back.. you put your foot down and it goes then pushes you back as it feels like ive hit the limiter but the powers comes back then goes again.. i have to constantly rev the engine to pull away as it will stall if i dont. when you take the air filter off the car gets worst and put the air filter back on car runs better but stills holds back ect.. when i press the brake the middle light on dash dims..no faults only airbag light.. getting worse and worse hard to drive without stalling.. i dont know if this did something but i ran without an air filter for couple of months so that might of done something. i put the filter back on and thats when this problem started happening.. at really high rpm it will clear and have full power but jumps while getting there.. so miss fire and holds back at low rpm at high rpm like nearly to the limter the car clears.. like a roller coaster power comes and goes and come and goes lol.. hard to say what it actually feels like.

--cleaned the MAF.(cleaned throttle body) unplug nothing happens.. getting 12 volts.. bought a used maf nothing changed so hoping to buy another one and hoping it works..

checked all coils and plugs... all sparks

no vacuum leaks.. sprayed around and no engine difference

all connection are fine. garage checked..

lambda sensor pre cat changed. brand new

injectors are working as they should. clicking always used fuel cleaner.

VVT changed couple months ago along with the cam belt.. (oil change)

could anyone help me as i have no clue what to do with it. i dont want to get rid as i really love the car, put so much money into it making it a head turner. dont want to get rid of it just by a sensor problem or something.
seen couple of forums that people have solved the problem but they never say what it is as they all sound the same as what im getting.

i personally think its air not fuel..
thank you for any comments!!

 

[Ziggy122]

Hmmm
Sounds like either a sticking Idle control valve
or there is an issue with the throttle position sensors
Its possibly not registering a fault - but the throttle body may be saying its open say 10% but actually its at 1% = Hence why it keeps wanting to stall

Live Data Reading would probably find the fault here

Ziggy

 

[Brendan W]

Could it be the power supply and or earth of the throttle pedal pot.

 

[s and b]

running a maf without a filter usually causes it to get coated with road film and thus go out of its determined parameters
ive never had long term benefits by cleaning these on any make
however
i dont think its your problem here
i would advise you do as ziggy says you need to read live data and see what is actually happening on throttle openings
to give you guidance i had a similar problem but overrevving with a panda not so long ago,i ignored the throttle body as it was clear it had just been changed for a spanking new one,bad prognosis this body was faulty
the only way after spending lots of time and energy was to plug my crp129 in or is you prefer a mew supported laptop and go on a drive the live data should pinpoint your problem

you say you did a vacuum test but the only way to do a proper test is with a vacuum guage these are £20 usually to buy and last a lifetime if not abused
you should be looking for a reading of 18 on tickover going to nothing when you give it throttle

to summarise stop looking in the sky and get a code reader that does live data one should be available for less than £30 now ask the seller if unsure

see like here
https://www.gendan.co.uk/product_FXNT200.html

 

[essexHGT]

Thanks for your comments. means alot..

i will go to the garage tomorrow and tell them to look at the live data at the throttle and sensor to see if there all correct. i will post to see what happens.

 

[flisko]

which are those alu wheels

 

[BILL33]

Is the cam belt checked that its in the right position?

 

[essexHGT]

hello, update..

the wheels are Lenso rs5.
banged the fuel tank while car is on the ramps and the car died straight away and struggled to up back up and when it does it runs really bad as in you cant build speed as lumpy.

needs a new fuel pump. ill be cleaning the fuel tank (mesh) as might aswell as its out the car and chance to clean the crap if there is any.

so if your cars what im having replace your fuel pump..
just saying as alot of people never say what fixed the problem.

 

[flisko]

so it was cuz of fuel pump