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99 UK S-turbo
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Discussion Starter #1
When I first test drove the car I bought it had a misfire/surge feel at WOT below 3000rpm, the dealer had new plugs and leads put on it and it was fine when I test drove it before buying, however its now come back. I also noticed this (slightly) on two other cars I test drove (but not a third). Its probably also made worse by the driveline 'slop' from the soft mounts.

As two of the leads weren't on the coil properly I will check the connections to the plugs when it stops raining so darned hard.

Anyone else come across this? any suggestions? I know I have a slight boost leak where the rubber hose joins the Y-piece under the IC (evidence of breather gas oil being blown out) but don't think it can account for all the problem!

Simon
 

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Discussion Starter #2
Anyone..........
 

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97 s/tb
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so you checked the leads then?
Can you explain the symptoms more? my first thought was the coil pack but it usually misses higher up the rev range rather than down at the bottom.
 
Z

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Check leaks at the exhaust manifold prior to front O2 sensor. Since yours is quite an old model there is possibility that the front O2 sensor is dead. Try changing this or get it checked
 

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first 02 sensor is in the downpipe on a SF turbo.
 

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Discussion Starter #7 (Edited)
I've checked the leads, all now appear to be fitted OK, I have also redone both the turbo to I/C joints as they were leaking a bit (some breather oil blown out), no exhaust leaks in front of the O2 sensor, may try a replacment, but it felt a little better this morning, so will try it on the way home before I commit. To be honest it feels more ignition than air/fuel based, but if it had a boost leak it would have been overfueling (even more than standard!) so may have been putting out the spark/fouling plugs (hence better on new plugs).

Sometimes you get a 'feeling' at part/light throttle its holding back, but at WOT upto somewhere between 2K and 3K rpm it either 'holds back' or blatantly misfires (jolting through drivetrain)....

Simon
 

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Discussion Starter #8
As an update, having tightened up the intake pipework, drove aweful first thing this morning but then suddenly improved, tonight it was 98% perfect, not sure its not 100% and me being picky...but I would now buy the car again (if you see what I mean!) I can only assume the EMS was fueling for the leaked air and fouling the plugs/overich and once I fixed the leak it took a while to adapt back, but I am a happy bunny again!

Simon
 
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