STPEngine Stop Leak for Petrol & Diesel Engines 300 ml, Improved Concentrated Formula, Conditions your Engine and Prevents Minor Oil Leaks, Mechanical Car Cleaning Products, Made in the UK

Arrived quickly from Amazon, we'll packaged. Put this in a full tank on my 2015 1.2 petrol DS3 w/103k on the clock about 2 weeks ago and so far looks good. My fuel gauge is digital and each quarter is split into 3 blocks, since I bought the car 2 1/2yrs ago I've been gauging fuel use by using the trip computer, trip 1 for each block and trip 2 for full tank, each block was going after about 28 miles, 30 at a push, so each quarter tank gave about 84ish miles, so a full tank was returning about 350 miles, my journeys are very much the same month to month, home-work-home, shopping or popping to MILs. Since I've put this in 2 weeks ago each block in the quarter of the fuel guage has been going off after 35 miles, so 105 per quarter so possibly signifying an increase of 70 miles or so for the full tank.Now in February I did have new tyres all round and a wheel alignment so the new fuel economy could be partly down to that but I have felt that the throttle response does feel much better, I've got this on subscription so planning to put this in my car and the wife's every other month and see how it goes but at first impressions it looks to be doing something positive

Really improves engine performance, I used the product in a 7 year old Citigo and it has improved acceleration and has made the engine even smoother. I will be using again and I would recommend. Easy to use just pour into the petrol tank.

Good quality and good value

Bought this for my 21 Yr old Honda Civic (petrol) with 144k miles on the clock...I usually bung some redex in once a month, which keeps it ticking over nicely, even tho I have to pay extra for the expensive 97RON fuel as it runs like I'm towing a caravan if I use the cheaper stuff. It had started hiccuping on acceleration from time to time, so I thought I would try this instead...what a difference it makes! Filled it 3/4 full then put a bottle of this in...within 5 miles, the old zip on acceleration was back again, have had zero hiccups from the car, its quieter on acceleration and I would guess (haven't compared) it uses less fuel now its cleaned the entire system...I have added a bottle of this to my subscription list for every 2 months, and have the same brand bottle for "high mileage vehicles" in the months in between...I usually blow out the cars cobwebs with a long uphill sprint to get onto the M25, but after using this, I was astonished how smooth the pickup was, and how easier the car revved...give it a go :)

used this with a full tank of fuel on my suzuki intruder 125 vl lc, for a few days i could tell all the gunk was making it's way through the fuel lines so the bike ran actually worse but once that all made it's way out of the exhaust the bikes runs and sounds much smoother

Good does what is says

So I’ll start by saying that I really don’t know anything about cars. Like almost nothing. So this review is aimed at people that share that similar knowledge (seriously like if I had to scale it; 3 out of 100 in car mechanics knowledge).My car was misfiring every day. Cylinder 4. Apparently, BMW said I needed a new fuel injector. At around £750+ all in, I decided I’d just get a new car (this one was at 155000 miles and 9 years old after all). However, after a bit of googling, I found that a common issue was that the fuel injector’s lines can get clogged up and cause the symptoms my car was dealing with. So I thought I’d try and give it one last push with the BMW before ditching it. Researched the best options and this one came out as one of the best for the money. So I gave it a go.It was super easy to pour in, as the neck is really long and slots right into where you put your petrol in. Couldn’t be simpler.I left it overnight and then went to work. When I started it up, my car continued to misfire just as before (it only did it when I hadn’t driven it for about 8 hours. Once it had been driving a while, I could stop and start to my hearts content). I didn’t notice any difference whatsoever. Other than the fact the fuel gauge had gone up slightly (hadn’t considered that it would basically be adding more fuel, sort of, so bonus!). It wasn’t until the drive home (having done about 15-20 miles total since adding it) that I noticed all of a sudden that the car had become a little smoother to drive. I noticed the acceleration also seemed a lot better. It only stayed like this for a few days though, before getting worse.It continued misfiring on every morning start up and I got fed up with it, so I just sold it and moved on.So, did it work? I guess it did improve the performance slightly for a few days. Maybe it would have done better if my car wasn’t already falling apart, though.Ultimately, for the money, I’d say try it. You’ll sort of get its value in petrol (when topping up your tank) and if you’re just looking to improve the overall performance and health of your car; it probably does that.

Gave a boost of about 4mpg in the the car I was driving.