Technical stumbling/lugging problem

[puntocab97]

Hi all, new to the forum. Just purchased a '97 Punto Cab, 1.2L S.

I took at look at past posts but didn't find anything that relates...

Car ran fine during the test drive but now that it is home the engine seems to 'stumble'. Starts fine, idles fine, but when driving (in any gear) from time to time the engine seems to stumble.

At first I thought bad gas (water contamination) so put in some injector cleaner, but no change. Last night I put in some gas with 10% ethanol (available here in France) and it was worse.

I'm thinking fuel filter (not sure when it was done - car has 82K km on it) so I will replace that and the plugs. Anything else to suggest? I saw a lot of posts about Lambda sensors.....could that be the problem given that the issue is very intermittant?

Thanks in advance for any responses...

 

[fingers99]

I'd check the HT leads and MAP sensor before the lambda.

Injector cleaner is a waste of money -- even French petrol contains injector cleaners.

 

[puntocab97]

Thanks for the quick response fingers99, I will look at those two points as well.

 

[blu73]

Welcome to FF! :wave:

Do you know the cars service history? Could just need a good service, so many fiats are treated badly and not regularly serviced.

By good service i mean all fluids and filters, plugs and HT leads.

 

[puntocab97]

Thanks Blu73! I don't know the history at all (except that the water pump and timing belt were changed). The car is very clean though (under the hood), looks like it was well maintained. I will attack the plugs, air filter, fuel filter,new wipers, HT leads and if possible oil change this weekend....

 

[puntocab97]

Oh and take a look at/clean the throttle body and MAP sensor!

 

[blu73]

good stuff, let us know how you get on

 

[puntocab97]

Well, I couldn't wait for the weekend, so last night I replaced the fuel filter, air filter, cleaned the air box and the throttle body, replaced the spark plugs and wires and replaced the wipers. Wow what a difference! No stumbling, smoother idle and more power!

I suspect that the fuel filter was orginal based on the condition it was in.

The air filter was due to be replaced, and the box was full of small leaves.

The throttle body wasn't too bad, but it didn't hurt to clean it up.

The plugs were relatively new, but the gap was on the high side, and plug #3 was black.

The plug wires were dodgy and due to be replaced. They looked like the original wires! (still marked FIAT). Wire #3 was wrapped in electrical tape....

The wipers were clearly due to be replaced - but I don't think that they were a key element to the improved performance

So many thanks to Blu73 and Fingers99!

 

[blu73]

good news! And yes nearly every fiat i look at still has its original fuel filter, strange as it clearly states its a service item in the service intervals and yet even cars with full fiat service histories usually still have the original one still.

If you not done it then i advise you drain, flush, refill and bleed the cooling system - should also be done regularly (i do it once a year) and i would bet from what you have said its not been done for a long long time

 

[puntocab97]

Good idea. I'll add that to the list when I do the oil change...gotta wait for the snow to melt here first....wasn't the best weather to buy a cabriolet but prices were right!

 

[blu73]

hehe, tell me about it, i have many many things i need to do to cars, my drive is still covered in snow though