Hi all

Have a Punto HGT 05 with 45k on the clock. It's in pretty decent condition I think for its age,
and has been serviced regularly but since I got it a couple of years back, noticed a problem with the revs.

When dropping gears (second on neutral) it will ocassionally dip quickly to below 1000rpm to like 300-400 and sometimes stall, sometimes bounce back up to 1000.

Took it into the garage for a full service a couple of weeks back and asked the mechanic there if he could take a look. Sods law & he couldnt replicate it, but did mention that it could be down to fuel if I was using the cheap supermarket stuff.

I did use to run it on v-power, but after moving house and it being local have had a few tanks of tesco unleaded recently. So have dropped a couple of shots of redex in between fills and gone back to v-power but it's still been occurring occasionally.

Checked round the forums and most seem to suggest cleaning the throttle body. Had a look today, and couldnt take it out fully due to the pipes and crap all light in my garage, but could see that it was pretty clean above and below the plate.
Gave it a quick clean with wynn's throttle cleaner whilst I was there, but failing that not sure what else it could be?




(Photo taken before the clean of the underside)

Any ideas greatly appreciated!

I have a fiat stilo 1.8 which is basically the same engine. I had the same problem.
I even bought another throttle body thinking it was the problem, but no, the revs will still drop.
So what i did is cleaning the whole throttle body. Cleaning all the plugs with contact cleaner. I even took apart the entire throttlebody and lube.
Next think i did was making sure the timing was correct. So i took the belt off the put the car on time with the camlocks and stuff.
Also cleaned the camshaft sensor which is the behind the exhaust sprocket.

After all of that the there is no rev dropping.
I actually did more that necessarily. I would start cleaning every contact.

astacheva said:

I have a fiat stilo 1.8 which is basically the same engine. I had the same problem.
I even bought another throttle body thinking it was the problem, but no, the revs will still drop.
So what i did is cleaning the whole throttle body. Cleaning all the plugs with contact cleaner. I even took apart the entire throttlebody and lube.
Next think i did was making sure the timing was correct. So i took the belt off the put the car on time with the camlocks and stuff.
Also cleaned the camshaft sensor which is the behind the exhaust sprocket.

After all of that the there is no rev dropping.
I actually did more that necessarily. I would start cleaning every contact.

Click to expand...

Brilliant many thanks for that!

Sounds like a bit of work and research, so may hang on until the weather & light is a bit better. It's been a little better this last week, can see it happening occasionally but the drop is less and manage to controller it with bringing a bit more gear and throttle in to level it out.

Have you come across any decent reference for this engine? Struggled to find much on it through HGT alone, know it's been used in Alfas and the Marea as well. Do really like the car and despite its age, do want to keep it going as long as possible. Was just a bit weary of disconnecting the hoses on the throttle body completely in case I couldnt get the things back on, or it would cause more damage!

Carburetor(!) spray is an excelent cleaner for the inside of the throttlebody!