Car doesn't drive smooth after sitting

#BrownRoush

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Can't remember the last time I posted here. Currently have a 2001 Roush Stage 2. possible to change my user name?

on with my problem:

I have only this occurrence only a couple of time, and only occurs under these parameters. It wasn't till I have a week off that I even noticed the car would do this.

If my Roush sits for about two days, when I first start it up and drive it, under part throttle, the car doesn't not pull smooth, like it has a miss or something. Idle is fine. WOT is fine.

After some time driving it usually evens itself out. Furthermore, if I let the car get warm(like middle of gauge warm) it usually wont do the miss. If the car is driven every day, it doesn't do it at all. Already replaced the fuel filter with an OEM, filter.

A few Mustang friends of mine said the Fuel pump may be on the way out. Would greatly appreciate any information to the cause.

furthermore, form yesterday:

Just wanted to update this, now my car seems to be miss all the time under light throttle, and bogs on WOT. idle appears to be fine.

just cleaned the MAF and checked the resistance on the COP's tonight. on a short drive the car did feel better. However, during the COP check i did unplug the car battery, So im still not sure if the cleaning or the reset made it better.
 
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#BrownRoush

#BrownRoush

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The fuel filter is a motorcraft, and maybe 3 months old. the COP's checked out good as well. I noticed the thread. how would i check the injectors?
 
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Not too sure. But if they are bad some how they're probably clogged. Not too sure a good way to check them other than saying fvck it I'm upgrading to bigger ones. Also check any wiring around the cops.
 

JerZeyStangz

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Hi #BrownRoush, this is just a hunch but I would look over the entire fuel system. Buy a pressure guage and hook it up to rail to see if fuel pressure is on the low side. I recently replaced my 88lph oem fuel pump from 96 with return style aeromotive 340lph pump for a upgrade and potential investment for force induction. Next look into the FPR or FPRS. Both of those items can mess with fuel pressure, and as a last measure make sure you gas cap isn't old either....

1) Fuel Filter (Check if there is blockage)
2) Fuel Pump (is it slowly dying?)
3) Fuel Pressure Regulator or Sensor (Is it old?)
4) Gas Cap (is it bad?)


Anytime I have certain issues I look at the whole system...hope that helps...
 
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Hi #BrownRoush, this is just a hunch but I would look over the entire fuel system. Buy a pressure guage and hook it up to rail to see if fuel pressure is on the low side. I recently replaced my 88lph oem fuel pump from 96 with return style aeromotive 340lph pump for a upgrade and potential investment for force induction. Next look into the FPR or FPRS. Both of those items can mess with fuel pressure, and as a last measure make sure you gas cap isn't old either....

1) Fuel Filter (Check if there is blockage)
2) Fuel Pump (is it slowly dying?)
3) Fuel Pressure Regulator or Sensor (Is it old?)
4) Gas Cap (is it bad?)


Anytime I have certain issues I look at the whole system...hope that helps...

[MENTION=19732]Ballistic[/MENTION]
 
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#BrownRoush

#BrownRoush

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Hi #BrownRoush, this is just a hunch but I would look over the entire fuel system. Buy a pressure guage and hook it up to rail to see if fuel pressure is on the low side. I recently replaced my 88lph oem fuel pump from 96 with return style aeromotive 340lph pump for a upgrade and potential investment for force induction. Next look into the FPR or FPRS. Both of those items can mess with fuel pressure, and as a last measure make sure you gas cap isn't old either....

1) Fuel Filter (Check if there is blockage)
2) Fuel Pump (is it slowly dying?)
3) Fuel Pressure Regulator or Sensor (Is it old?)
4) Gas Cap (is it bad?)


Anytime I have certain issues I look at the whole system...hope that helps...

Solid advice, ill check it out
 

Nighttrain

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A guage will tell you most of the time what is going on. To check your injectors disconnect each cop and do short cranks. If an injector is bad they will usually leak by. If you see the pressure bleed slowly out of the rail...bam injector. The guage can also tell you if your pump or regulator is bad by what ever the pressure is at the rail obviously. The problem balistic and frankie were having ( correct me if im wrong) was #7 plug fouled out. Dont go crazy buying cop's from oem unless you want a specific performancey, fancy, schmancy one. You can get them from your local you pull it for pretty cheap. Next and last, you fuel filter even if its only 3 months old could still be clogged. If you dont drive your car alot, ethenal will gum up everything, or just plain got a bad tank. It happens, that would be the first thing id check. E85 might be great for go fast but ethenal is horrible for rubber anything and is good at collecting water.

Just my 2 cents
 

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