Hi all,

Today I cleaned my throttle body to try and solve the rough idle and hesitant acceleration on my 1.2 8v Mk2 Punto.

Had no issues completely removing the throttle body from the car and proceeded to clean it with a rag, toothbrush and Wynn's Fuel Injection and Carburettor cleaner which specifically says it is suitable for use on throttle valves. I put everything back together and went for a drive so the ECU could relearn optimum settings and to check everything was working okay. Did 10 miles and all was okay. However when I used the car later, it started to judder massively, with the engine management light flashing while it was doing so, however this would stop if I took my foot off the accelerator. I drove back home, with this happening intermittently and I couldn't work out any relation to either revs or accelerator position, for example it happened at 35 mph in 4th with little acceleration, and at 10 mph in second with high acceleration but not at 30 mph in second when I was trying to replicate it.

Any ideas as to what is causing this? My only thought is either the throttle butterfly valve is getting stuck, or one of the sensors in the throttle body is malfunctioning.

Many Thanks,

Matt

Puzzling as to why this should happen when the car was OK.

I wonder if this is an unrelated misfire?

Try removing as much of the air filter housing as you can, get someone else to run the engine, work the throttle (ideally at night or under a blanket) look for blue flashes, check the throttle butterfly is opening. Unplug and re-fix any electrical connectors going to the throttle, preferably using a little silicone grease first.

If you do see blue flashes, check where they come from, but you almost certainly need new HT leads.

i think as fingers has said disturbed a HT lead

lacking power and EML flashing is a surefire misfire signal

I too would say get the airfilter off and check all connections are clean and tight and not going anyway

If this doesn't seem to fix, find out which cylinder has started to misfire

Ziggy

Took the air filter box off today, checked all the HT leads and the leads going to the throttle body, all seemed okay. Checked the throttle butterfly valve action and again all was okay. Refitted the airbox and went for a drive.

I had one small judder, but not like the judder before which continued until I took my foot off the gas - this was just like a very momentary loss of power and only happened once. Later on I went to work in the car, did 40 miles in it and not a sign of a misfire at all - I was able to enjoy the difference the throttle body clean has made to the car!

Could remnants of carb cleaner in the throttle body have caused the misfires?

Thanks for the help though guys, I'm glad its all sorted now

I'm pretty sure it'll turn out to be electrical -- problem is, finding out where!

Did you remove the throttle body before cleaning it?
or did you just spray it while it was on the manifold?

if you sprayed it while still attached, then that explains ALOT

otherwise, i dowt it

Ziggy

Fingers - The car is fine now, done about 60 miles in it now with no sign of any trouble.

Ziggy - I completed removed the throttle body from the car to clean it.

Whatever the problem was it seems to have resolved itself now so I'm happy

Matt

Sounds like the cleaner was still in the throttle pot..