car_issues

Hi All,

Firstly let me give you some car specs:
- Mazda 3 1.6TS (diesel - no modifications from stock)
- Year: 2006
- Mileage: 78k

I've had the car for a number of years now and no problems, however recently (last 12 months or so) it's been a little hesitant when pulling off and doesn't seem as responsive as it once was. I've had the occasional issues starting up (albeit rarely) where it didn't really want to start until I revved it. I also had some fume issues when I turned the internal blowers on, I was assured this was related to the injector seal and return fuel line and this is mostly resolved. I've also had the CEL on since using some Redex (seems coincidental?) but the issues with responsiveness and idle issues pre-date this.

Work recently undertaken (last 12 months):
- Alternator replaced with new (as it had failed)
- MAF sensor replaced with new (yesterday)
- Injector seal leak (cleaned and new seal)
- Return fuel line leak (replaced pipe)

CEL Error codes: (Only have an OBD2 scanner)
- P2584 - Fuel Additive related (I cleared this since installing the new MAF but it has returned.)

(Obviously when i disconnect the MAF i get just the sensor error ones)

Now the problem I've got is that in the last couple of days the car has sporadically been really bad. For example, I was on the motorway cruising (70-80mph) and all of a sudden the car began to lunge repeatedly and wouldn't go over 2.5k/3k revs. This then stopped and the car returned to normal. It did this a couple of times over the course of a longish journey (300miles).

The car also idles roughly and when i go to stop at lights there have been a few occasions where it seems like it's about to stall but then recovers.
Now, when I had the car running it would idle very rough (low revs), if i turned the aircon on (regardless of hot/cold) there would be a loud click noise coming from under the bonnet which happened every 5-10 seconds or so (I presume the aircon going on/off) and the car would idle horrendously, dropping revs every time the click occurred. I started the car again this afternoon and when I turned the aircon on it clicked and then the car stalled. I turned everything off and disconnected the MAF - the car now runs fine (with or without aircon), no rough idle and no hesitation issues - it's exactly how it should be (from a driver's perspective anyway).

Something that may be relevant: I'd cleaned the MAF before replacing and it made no difference (using the correct cleaner and ensuring it had dried etc), it was covered in crap, so too was the air pipe connected to it and some had gone into the air filter. I replaced the filter and cleaned it as best I could however it's still not spotless... any ideas what caused this - i presume it's not normal...)

Would it seem right that the fuel additive code has caused all of this?

Would the MAF need to be connected (i.e. plugged in) in order for the engine to throw the P2584 additive code (because when I clear the code and disconnect the MAF I get no additive CEL codes so it seems odd?)

Can anyone help point me in the right direction? I've already spent a fair bit trying to get this solved and it's getting to the point where the car isn't worth the money i'm spending on it.

Thanks in advance!