STP Diesel High Milage Injector Cleaner 200 ml, Cleans and Protects your Engine for 300 miles, Enhances Fuel Economy, Mechanical Car Cleaning Products, Concentrated Cleaning Formula, Made in the UK

Did the job perfectly. I have only used one of the bottles so far. My diesel engine started running a bit rough and felt like she might cut out when I was stationary at junctions. She's an old Kia Sorento. I figured before I booked her in for exploratory work, I'd add the bottle to my next tank of diesel and it worked. One day, when I put my foot down hard, I could see a puff of black smoke come out of the back of the car (after I'd used this additive) and have not had a problem since. I think it cleared whatever gunk was in the fuel system. I'll be using the second bottle in about 6 months time. I used the Diesel Injector cleaner first. I'll use the Diesel System cleaner next.Good price and super fast delivery. I've only used the injector cleaner so far and driven around 100 miles but the fuel economy has definitely increased and the engine noise has gotten quieter so i'm happy to recommend.

Very good quality value for money easy to use

STO products are very good and do the job depending on how old your vehicle is and how clogged your injectors are. Over 100,000 miles on my car and so far one injector replaced. This product does smooth out the idling and improves performance if used regularly as advised by the manufacturer.

I'm usually dubious about these type of products as they seem to be a hit or a miss. My van was a little grumpy on startup and noisy to drive but after using this it seems to have restored a little bit of power and the engine is running smoother and quieter than before. It obviously helped clean up some gunk and residue in the injectors.

Within 10 miles i suddenly started feeling the car was driving smoother, it was amazing how in cold morning starts it started immediately when i turn the key, no jerkiness due to it being cold.Then i went on a 100-mile trip the day after I put it in the tank, and my MPG exploded, i even had a game with the kids to see if i could get it higher, while keeping up with traffic, and reached 54 MPG at one point but, that was with a bit of neutral on long hills, not much mind you, there was a lot of stop starting as well.After a few days of normal driving I now am running at 48mpg, it is something i have never experienced in my car since I bought it 7 years ago, it has constantly been running at around 28mpg , 2007 ,model ford galaxy 2.0tdci. For those that use km a liter that is around 18km per literI think if this lasts a while, i am going to put in a bottle every third tank of fuel.

Cleaned my old diesel right out, great. Genuinely improved mpg which surprised me

Magic stuff. I'm dubious of products like this because I know cars need looking after properly and there's no magic wand.I have an old diesel that's fast approaching 150k. It was running rough, down on power and idling all over.I thought I'd try this pre a service. Put it in with a full tank and honestly forgot I had. After about 50 miles it's back to normal. Beautiful idling, power back.I've decided to use this with every full tank going forward it's magic.

I've been using this in my car for 9 months now and cannot say I notice any difference. It might run slightly smoother but no difference in MPG or build up of carbon in the EGR valve. Still struggled to pass the emissions test too. So disappointed with the results od a long term test.