98 LSC acting up - help!

46callaway

46callaway

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The car was misfiring yesterday at idle but I ran some fuel injecter cleaner and put the tune back to stock and it seemed to idle better today but still a bit rough. The car revs up really slow and it won't even spin the tires off the line anymore! Before if I floored it off the line it would do a one leg smoke show half way down the block. There is no CEL or any codes. The misfire seems to be intermittent at idle, sometimes it happens sometimes it doesn't but when it does I can definitely hear the popping out the back of the exhaust.
 
Check your coil boots... that is how mine failed...

Disconnect the coils one by one... and once you find the one that doesn't make the idle worse pull it out.
 
maxmk8 said:
Check your coil boots... that is how mine failed...

Disconnect the coils one by one... and once you find the one that doesn't make the idle worse pull it out.
Click to expand...

That would be my first guess as well, also make sure you don't have any water in the wells.
 
I installed all new silicone boots about 20,000 miles ago but oil is seeping past the gaskets a bit. I will check that tomorrow and replace the plugs with some copper NGK TR55. I have some Platinum Autolite 103's in there right now.
 
You should figure out which cylinder is misfiring first. before you start throwing parts at it.... 1/8 is much easier to deal with than all 8.
 
I ran seafoam today through the PCV valve and changed plugs today. When I was lurking around the PCV valve I noticed the vacuum line going from the pcv to the intake manifold is really cracked badly and causing a vacuum leak. Unforunately the Ford dealer can't get this until Sat. I drove around with the new plugs, went to starbucks. When I restarted the car it really started running rough, almost stalling out at idle. It clears up completely from 2500rpm up. The CEL light finally came on when I got back home but I dont have a code scanner. I figure this vacuum leak is causing unmetered air to go in and causing the roughness and hesitation. Does that seem like something this vacuum leak would cause?
 
I did tape the line but it's pretty much collapsed it's cracked so badly. I got the code it's lean on one bank. There is so much vacuum running from the pcv lines, I had the motor running and unplugged the other side that's not cracked which goes into the intake manifold and the car stalled out right away!
 
OK well the new PCV line did not fix the problem. The throttle response is extremely delayed when you snap the throttle, any ideas on what to check for next? Codes show lean on both banks.
 
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About 15k miles ago, the Ford dealership found the problem, it's the fuel pump. I ordered an SVT Focus pump and it will come in Monday.
 
46callaway said:
About 15k miles ago, the Ford dealership found the problem, it's the fuel pump. I ordered an SVT Focus pump and it will come in Monday.
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The fuel pump would have been my next question since it sounded like you had a fuel issue. It is not uncommon for them to fail on the Mark VIII, the 100k mile mark or there about appears to be the time the fail when they do go.
 
I know it is strange but they tested the fuel pressure and they said it was so low they don't know how the car was driving at all.
 
Wait this was 15k miles ago?

I am a bit confused by your previous post... if the FP is low then it makes sense to replace the pump. Is the FOCUS pump a direct drop in? I know you can't use the walbros on a Gen II.
 
No, I replaced the fuel filter 15k miles ago. The car started to act funny, slow response, down on power about a week ago but the fuel pump has probably been weak for awhile. I knew something was wrong since my mph dropped from 97 to 93mph at the track. The SVT Focus pump flows enough for up to 430rwhp and is quiet as stock and is almost a direct swap. Two wires need to be spliced and you reuse the stock MK8 basket.
 
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