loss of power

I am really not sure about this so thought I would post to see if other have or have not felt this.

I feel like I am having a loss of power or at least a hesitation before the power comes in.

The first time I had the 'feeling' I get was driving home from the meet at MK. I was being followed by a Porsche on the motorway, we were both in the outside lane behind slower traffic. When the traffic cleared I dropped down to 4th and booted it. I took off nicely and went through the rev range in 4th and then 5th but when I pulled 6th it just went nowhere. It almost felt like I had a little misfire. I had to let the Porsche go and was left being a little disappointed about the top end power. Don't ask how fast I was going as I genuinely don't know.

I never thought anything about it again and in fact I didn't feel anything again until this weekend. We have actually had some dry roads and I have been out for some 'spirited' driving. I have had some really good drives but I keep getting a hesitation that feels a bit like a misfire.

Before anyone says, I am 99% sure its not traction control coming in. I feel that all the time. Its a lot more subtle and not when I would expect it.

For example I will get it when I put my foot down on a dry road in fourth gear. Just not a time when I would expect to feel traction control working. When the power comes in it is sudden, its a little like turbo lag but before the power comes in I can almost hear/feel a misfire.

Anyone else experience this?

nothing with the s550 but used to get it with the old car. might just need some injector cleaner. Are you using supermarket gas? or petrol station gas?

Cati said:

nothing with the s550 but used to get it with the old car. might just need some injector cleaner. Are you using supermarket gas? or petrol station gas?

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I use a mixture. Mainly petrol station. Are you honestly suggesting there is a difference?

Is it always on the same rev range? Same gear? Same speed?
What mods have you done? CAI or exhaust?
I have no answers but it may help with your issues.

Try using V power or tesco 99 for a bit and see if it helps

Everything from Air filter to tail pipes is stock, I have made no mods at all other than cosmetic.

It is at generally when accelerating when car is doing 30 to 40 I guess. Except that one time on the motorway.

Get the dealer to run a diagnostic check, also, check the HT leads are all properly seated, generally have a look over any engine bay cables, might be something not making a connection sporadically.

yes i am suggesting there is a difference.... there is a reason why it is so cheap

It's your cheapest diagnostics test. Run a tank of super through it and see if it helps.

Cati said:

yes i am suggesting there is a difference.... there is a reason why it is so cheap

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I would need convincing of that. Tesco don't make the petrol, they buy it. Plus our Texaco and BP stations are selling for the same as Tesco and Sainsbury.

Fact is the car should run on all these fuels. I will try some V Power as suggested but it should not need it,

With my previous car forum, there was proof that using lower grade fuel caused an engine failure. These cars did however tell you to use high octane fuel.

I would personally only ever use V power or tesco 99. And the price these days is so cheap it seems silly not too IMO

HI there


1. In 6th these cars are useless, the gear is an overdrive, geared for well over 200mph, in order to have good acceleration in this gear you need a supercharger. But 5th is good for around 150mph, if your trying to go faster than this then forget it for now as 6th is like hitting a wall.

2. All I have noticed but could be TC system as I've not had much dry weather, but say I bury the throttle in third instantly at say 2000rpm, the car seems a bit slow at picking up and once 3000rpm comes it gets noticably quicker and pulls way harder. Almost like 2000-3000rpm can be a dead zone if burying throttle too quick. If I roll into the throttle so I am not overwhelming the engine with too much air at once, I don't get this.


However I need to do more testing, do I think its an fault, no, a characteristic yes or maybe a function of VCT. Have I ever witnessed a loss of power over 3000rpm full throttle, nope the car pulls to the limiter very hard and quick in the first 4th gears, have not tried stretching its legs in 5th.

stevec said:

Fact is the car should run on all these fuels. I will try some V Power as suggested but it should not need it,

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Should, and will. Run at it's optimum performance however...?

I've been running mine on either BP or Esso 97 and gave it it's first tank of Tesco 99 today so I have no frame of reference for using lower RON fuel in the Mustang.

The diesel X-Type Sport I had OTOH.....there was a definite difference when using V-Power (99% of the time) compared to the regular stuff (and not just the horrendous cost!).

In short, stick with the good stuff & at least that way you know it won't be the fuel causing an issue (barring a contaminated batch).

Yeh, been doing some research. Does seem that Supermarket fuels may not have the same additives
Not sure this is my problem though as I would say I use 50/50 V power anyway maybe more. If the V power pump isnt available I just use a normal pump

stevec said:

Yeh, been doing some research. Does seem that Supermarket fuels may not have the same additives

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Let's not get people started on this debate, before we have the 'cheap fuel' fans shouting 'Its a smear campaign' and the 'Proper fuel' camp shouting 'Yours is watered down crap' (BTW - I'm a Shell only user - for my corsa, pulls about 10mpg better... Shit car, but i'll take it, works out better )