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Flat Spot Just Off Idle


Vevapower

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  • Waiting for the 1st N/A 12!
  • Donating Members
  • Member For: 16y 2m 12d
  • Gender: Male
  • Location: Sydney

Hi guys, notice just recently that my BF has a slight flat spot just off idle or if you're just cruising and lightly touch the pedal you can feel it too, but you feel a sort of hesitation with a light power coming on off. But get her up over 1500 or slightly on power and sweet as strong as ever no dramas at all! :buttonit:

Actually when you start from cold and tap the accelerator slightly it has the tendency to stall occasionally, but the problem seems to be less noticeable as the car warms up and you've been driving for a while.

The Cruise control will now not work and I feel that this is all connected somehow.

Tuner thinks it might be throttle body related!!! :shocked:

I've searched high and low on all forums but not been able to find anything close to my query!

Anyways I hope some guru out there can give me some advice or fix.

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  • Member For: 17y 15d

I used to have something similar and finally found the Fuel pressure at 1500-3000rpm was set below 50psi.

- It was in fact 29psi!

Base Fuel pressure should be 50psi!

It would be worth your Tuner having a look at this Data!

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  • Waiting for the 1st N/A 12!
  • Donating Members
  • Member For: 16y 2m 12d
  • Gender: Male
  • Location: Sydney

Hmmm yeah sounds plausable and a possible reason for the flat spot!

I'll have the Tuner look at this, this week and let you know how I get on!

I need to sort this out sooner than later as the car is now for sale!

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  • 1 month later...
  • Formerly EGOBFXR6
  • Donating Members
  • Member For: 16y 2m 18d
  • Gender: Male
  • Location: Perth, WA

Hey mate,

I had this issue on my car very recently... I'll let you know what I did to fix my car. Should take you about an hour and about $20 to fix. And if it doesn't work, you haven't lost anything and you have a cleaner throttle body :spoton:

I had that flat spot, real rough idle and light throttle resulted in the revs dropping off; Sometimes to a stall... Also had the tendency to want to stall when braking to a stop.

Here's what I used and what I did;

Some sockets/ring spanners/screwdrivers

Can of throttle body/carby cleaner and rag

Fuel treatment designed to clean fuel system and injectors - I used Nulon

D/C the battery

I removed the air filter and cleaned it along with the air box.

Removed the X-over and hot-side/cold-side piping. Blew them out with some compressed air.

Removed X-over from throttle body and moved slightly out of the way so it was easier to clean the TB

Gently opened the TB butterfly and wedged a rag in one half of the opening to hold it in place

Sprayed TB cleaner in to half the opening, wiping off any excess, then wiping again after it has soaked

Same to the other half of the TB

Tightened all clamps/hose fittings appropriately

Air filter/box back and re-connect battery

Restart car - It will turn over a few times and will start and run rough for the first few minutes.

Then should be all good :) Head to the servo, add the fuel additive in case it is an injector/fuel system issue and fill up.

If that doesn't fix it, you've tried a cheap an easy fix - And ruling out issues is the next best thing to help you fix it!

If that's not it, there is a chance it could also be; (From my research)

Fouled injectors

Fuel filter clogged and needs replacing

Injector/fuel system issues

02 sensor issues

Fouled plugs,

Coil pack failure

If that fails, a bad tune or computer/timing issues.

I think you'll find it is the TB issue - It is very common in the BA/BF series.

Hope that helps mate :spoton:

Dan

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  • Waiting for the 1st N/A 12!
  • Donating Members
  • Member For: 16y 2m 12d
  • Gender: Male
  • Location: Sydney

Hey mate,

I had this issue on my car very recently... I'll let you know what I did to fix my car. Should take you about an hour and about $20 to fix. And if it doesn't work, you haven't lost anything and you have a cleaner throttle body :spoton:

I had that flat spot, real rough idle and light throttle resulted in the revs dropping off; Sometimes to a stall... Also had the tendency to want to stall when braking to a stop.

Here's what I used and what I did;

Some sockets/ring spanners/screwdrivers

Can of throttle body/carby cleaner and rag

Fuel treatment designed to clean fuel system and injectors - I used Nulon

D/C the battery

I removed the air filter and cleaned it along with the air box.

Removed the X-over and hot-side/cold-side piping. Blew them out with some compressed air.

Removed X-over from throttle body and moved slightly out of the way so it was easier to clean the TB

Gently opened the TB butterfly and wedged a rag in one half of the opening to hold it in place

Sprayed TB cleaner in to half the opening, wiping off any excess, then wiping again after it has soaked

Same to the other half of the TB

Tightened all clamps/hose fittings appropriately

Air filter/box back and re-connect battery

Restart car - It will turn over a few times and will start and run rough for the first few minutes.

Then should be all good :) Head to the servo, add the fuel additive in case it is an injector/fuel system issue and fill up.

If that doesn't fix it, you've tried a cheap an easy fix - And ruling out issues is the next best thing to help you fix it!

If that's not it, there is a chance it could also be; (From my research)

Fouled injectors

Fuel filter clogged and needs replacing

Injector/fuel system issues

02 sensor issues

Fouled plugs,

Coil pack failure

If that fails, a bad tune or computer/timing issues.

I think you'll find it is the TB issue - It is very common in the BA/BF series.

Hope that helps mate :spoton:

Dan

Cheers Dan some great tips there mate!

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  • Formerly EGOBFXR6
  • Donating Members
  • Member For: 16y 2m 18d
  • Gender: Male
  • Location: Perth, WA

No worries guys,

This problem is so common and usually such an easy fix, but no-one anywhere seems to know about it...

Like I said, it's a cheap and simple fix and you don't have to have any mechanical knowledge. $20 and an hour seems good to me :spoton:

If this isn't the case, and your car is still acting up have a look into the other suggestions. Most of them are cheap fixes too. (These are for parts only, but labor shouldn't set you back too much)

Fuel filter - $30

Plugs - ~$100

Ford can test for individual coil failure - About $70 for a failed coil

Fuel/Injectors - Could be anything... :dontknow:

02 sensors are easy to diagnose by ford/tuner - Not much $$ :)

Computing/Retune - whatever your tuner charges

Good luck mate, let us know how it turns out :beerchug:

Dan

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