STPDiesel Fuel Additive Twin Pack

I was advised to get this by my garage for my wife’s now 20 year old diesel Audi. It had failed emissions on one MOT, but that is because she doesn’t use it much for longer trips.Easy to use, the car seems a little quieter, and it sailed through the last MOT.Well worth the money.

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.

Bought due to black smoke emissions. So far fuel economy has improved but still have emission issue. However van has run less than 1k miles since adding so will wait and see.

Good stuff

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.

Great to use, used before, does what they say

The body of scientific evidence proving the efficacy of this stuff is essentially zilch. And did it work for me? Also entirely unclear. Maybe it made a marginal improvement for a time? Who can say really, tests on one vehicle are next to meaningless. But did it hurt the car or its engine? No, not at all.The brand clearly trade on "it's worth a shot" and who am I to argue. Especially since critical reviews don't need the Amazon guidelines!

Fiat Panda 2017 Diesel - 73k miles. Issue was momentary reduction of power when accelerating whilst the car was warming up. No engine check light though. Suspected it may be dirty injectors.Poured this in and filled the tank. Then ran until the tank was almost empty. That was over a month ago. The issue has now disappeared.I suppose the effectiveness of this treatment depends on how bad the injectors are. Worked for me though. I’ll use it again after another 3k miles.