Hello, I am from Europe and have a Ford Fiesta 1.3 duratec v8 with about 245.000kms.
A few months ago the local independent garage swapped the spark plugs and cables. It ran a little rough but when I talked to them about it they said it was going away by itself. I eventually started troubleshooting myself and cleaned the air intake housing, throttle cable and sprayed the TMAP sensor and ignition coil contacts with contact cleaner. Also I put injection cleaner in the tank. Long and behold, it actually worked and the car would run excellent.
Now, the check engine light is burning for years. A scan at the Ford dealer at the time said the cat was clogged but the emmissions were still within spec.
So now I thought, lets put cat cleaner in the tank. I put it on half a tank and hit the highway. It slowely started stuttering and after about 100km when slowing down on the highway because of traffic it started stuttering heavy and the check engine light started blinking and I lost power. I barely could drive 100km/h. I drive to a gasoline station to fill up and drove e couple of 100kms in this state. No problems with starting, rough idle and sound like the exhaast was leaking.
Now I brought the car to my local mechanic again to check it out. They said it is a faulty ignition coil but I doubt that it is true. Because I see a cause with putting the cat cleaner in. Another guy, from an autopart store where I bought the cat cleaner, says it is probably debris in the cat comming loose and they is have to burn overtime and glogginf the airstream up.
What do I need to do and who do I believe? The local mechanic put a new coil in and says they didnt find cat problems. I can go get the car in am hour.
Thanks already!
If the catalytic converter is suspected of being clogged, test it with a back-pressure gauge.
Ford Fiesta 1.3 duratec v8
It's an I4 8V (8 valve, not a V8...)
Because I see a cause with putting the cat cleaner in. Another guy, from an autopart store where I bought the cat cleaner, says it is probably debris in the cat comming loose and they is have to burn overtime
Welp... the symptoms you described can be fuel system related.
They said it is a faulty ignition coil but I doubt that it is true
It can be true, my personal experience with coils going bad always was related to using shady fuel.
I mean a coil / coil pack is probably not too expensive (usually about 75 euro) on an old Ford, if so, just replace it and see how it affects the engine performance
they didnt find cat problems
The way to check if an engine running roughly / having a low power issue is by the cat is simple: You take out (and disconnect) the upstream O2 sensor and see if the car began to run significantly better after a cold start (while the system is still in the "Open Loop" control state) - this is assuming the upstream O2 was functioning correctly but that's easy to check (once warm and in "Closed Loop", the readings should bounce)
Thank you both moderators. I will go check the cat from the video provided. I drove a bit and it seemed to be good now. Will drive longer today.
Can you please explain how nasty fuel affects the coil? Since there is no direct contact. Maybe the question is simple but this is my level of understanding at the moment. Thank you so much