Hi everyone, I'm hoping for a bit of help please.
I've got a 05 1.6 focus thats missing really bad under load.
Read the codes and it said MAP senosr fault so had this changed tonight, but it hasnt made any difference and it's now not throwing out any codes.
Anybody got any ideas what it could be?
Thanks in advnace
Donna

 

Most common cause would be an ignition fault. Check spark plugs and HT leads.

Second most common would be the MAF, whenever the MAF is suspected, simply unplug the multiplug and run the car with the MAF unplugged. The car will then use a base map rather than the live data from the MAF, if this resolves the problem then your MAF is at fault. Running the car with the MAF unplugged will generate a fault code.

Might be a problem with the injectors.

Could also be a vacuum leak or the heated O2 sensor.

I am assuming that it isn't missing at idle. If it is missing at idle, it could be an electrical connection (check battery terminals clean and tight and check all wiring). Could also be the ECT or a fueling problem.

 

Many thanks for the reply.
Probably should have mentioned that I've already changed the spark plugs and the coil pack. Ive read a lot about faulty coil packs so cant help thinking it might be that....is there any way to check a coil pack??
My focus doesnt have a MAF sensor, at least not one I can find, when I googled it, it said some 1.4's & 1.6's had MAP sensor instead of MAF sensors.
Its not missing at idle or when revving, just under load.
Seems there are quite a few things it could be then

Thanks again for your reply

 

Did you change the HT leads when you did the plugs and pack? Might be worth a check if not.

 

Sorry for the late reply.
Common sense would say I replaced the HT leads, but I didnt.
Anyway I bit the bullet and purchased new coil pack, new HT leads and new spark plugs last week (as euro car parts had a sales on ) as this has cured the misfire
However.....
I still have the problem that started all this. I can be driving along and the speedo will drop to zero for a few seconds (although I can still accelerate) and if the radio is on it will go quieter, then it will suddenly kick back in. Everybody I have spoken to says a new coil pack would have sorted this, but it hasnt....any ideas?

Thanks again for the help so far, I really appreciate it

 

Replace your vehicle speed sensor. Both of the problems you mention are caused by it. Be careful though, replacing it isn't an easy task in some Focus models.

FYI, your radio uses AVC (automatic volume compensation [or something by the like]), which increases volume as your speed increases.
I would not be so sure it had something to do with the misfiring, but hopefully that's completely solved by now.

 

Check the earth straps as well. I think the one at the back of the engine is prone to snapping and this causes the speedo to drop

 

Thanks for the advice
Yeah the misfire has gone completely and I'll now look into replacing the vss....or getting my mechanic to do it if is going to be a difficult job.
Thanks again

 

Thanks for the advice, I'll check that first before I invest in a new vss