View Full Version : Loss of power when accelerating

4th January 2001, 09:07
I've just had a major service on my 95 WRX and since the service I've noticed the following problem. When accelerating from standstill or even when moving the engine splutters and loses all power for a second or two. It feels as if there is no fuel getting through or a blockage ???

The service included a Fuel Filter change and new plugs, I asked if they used Platinum plugs. They replied yes, Bosch plugs. ???
The price of which was 8.20 each, normal price of NGK Plugs is 14.99.

Could this be a detonation problem with the cheap Bosch plugs ?

Any help would be greatly appreciated.


4th January 2001, 12:04

Could you be a bit more specific about exactly what conditions cause the symptoms you have descibed? Ie is it with the engine on vacuum, no boost, medium boost, full boost, and what sort of RPM?

What you have descibed thus far does not sound like a detonation problem, more of a miss-fire. Is it a total loss of power, or more of a sputtering? Does it always go away at a certain RPM point, or is it always a certain amount of time after hitting the loud pedal?

A fuel filter change could be to blame if the replacement is too restrictive, but this would oly be a problem at high boost levels. New plugs could be a problem if the plug gap is too large (should be about 0.7 to 0.8mm) and/or the coil packs are on their way out. This often shows up after a service....

<Short Circuit Quote> "Need Input!" </Short Circuit Quote> :)



4th January 2001, 12:11

The symptoms seem to be more of a sputtering nature on medium boost at around 5000rpm.

This has happened a number of times when the engine is cold & warmed up.

It eventually goes away, also if you ease off the throttle. You have to drop the revs below 2500rpm to pick up any form of pulling power.



4th January 2001, 18:13
I agree with Pat,

Check the:

Plug wires
Coil Packs
Fuel Filter
And boost Solenoid (Oil contamination) - Who knows


5th January 2001, 11:17

a sputtering doesn't sound like a fuel cut or anything of that nature, it's too "soft", so it's highly unlikely that it's a boost control (ie overboost) problem. Sounds more like an ignition problem, and the fact that it is transient in nature seems to point toward either too large a spark gap, or breaking down coil packs.


wires, which wires? there are no plug leads on a 95 model year! :) :)

Other than that, agreed, could be any of the items listed, but gut feeling says it isn't a fuel problem (it would be a more persistent than a transient phenomenon, surely?). Boost control certainly possible, maybe it's overboosting enough to blow the spark out but not enough to get the ECU to do a boost cut....



5th January 2001, 14:01
Just been to the Garage where I had it serviced & went for a test drive with mechanic. Fault never appeared straight away but after 5 mins at 5000rpm it happened, "Sputtering". He said that it seems to be an electrical problem with ingition and the cars going in on monday to be looked at. Checked the Coil Packs and they were fine, so it looks like it could be a wrongly gapped or faulty plu ??

Thanks for all your help chaps...


Bob Rawle
5th January 2001, 23:07
Plugs won't be "faulty" but they will be the wrong ones, they will be "blowing out" under boost meaning that the spark can't jump the gap. Put in the NGK PFR7B plugs gapped at 0.7 mm, should solve it. (Or HKS S35i's)


6th January 2001, 09:21

Just checked the bill from my service and they seem to have installed "Bosch Super 4" plugs. When I asked yesterday what plugs they put in they said "NGK Platinum".

So it appears that the wrong plugs have been installed, I'll make sure that they install the correct ones.

Thanks for your information.


9th January 2001, 12:47
<one liner> I still think it's coil packs </one liner> :)

9th January 2001, 14:19

Congratulations... You were right !!!!

Well I got my car back yesterday afternoon and the fault was caused by dirty coils packs, the OSF coil pack was tracking and causing the problem. It was very dirty and caked in Engine Coolant... I remember when I first went to pick up the car there was smoke coming out from under the bonnet when it returned from a test drive. He mentioned that a little bit of coolant spilt down the side of the engine and he'd wash it off, nothing to worry about ??

Thanks.... http://bbs.22b.com/ubb/biggrin.gif

[This message has been edited by ndouglass (edited 10 January 2001).]