Headers on a 4.0 SOHC

[410Fortune]

Agreed
Plug wires most likely

 

[Explorer2010fabricateBTF]

Im not aware of anyone having issues with them. What kind of issues are you having? Idling high, misfires, etc?

The headers shouldnt make a big enough difference it would warrant supporting mods to make it run right.

I have a rolling idle up and down. I have replaced injectors, New Motorcraft EGR,MAF,Fuel pump,FPS as well FTPS,Purge Solenoid,Canister,New PCV, Crank and camshaft sensor and Both upstream 02’s replaced twice now. Still Getting P02198 Rich also P0300 Misfires 1,3,5,6 New coil as well. Tried spraying at cool start up around intake, as all intake seals replaced when installed Bosch injectors. Is there a common vacuum leak or a pinpoint location the plastic intake can crack to focus on. Next step smoke machine. I forgot to mention New Cats have very little run time. As watching my 02 sensors on test drive start out at 6.50 then work their way up to 9.00-9.50 rich out. Fuel trims upwards of -25 then they all zero out go to limp/default. PCM was tested out run through live simulator and updated software as well check out good and sealed up. Real PITA.

 

[410Fortune]

If you clear the code and the misfire code appears very quickly then suspect the injectors
New out of the box injectors can be bad
Does your fuel smell of oil?

A misfire code that appears quickly is usually an injector
The computer cannot detect which cylinders are misfiring through the ignition, it takes several drive cycles. But a misfiring injector it can detect right away

 

[Explorer2010fabricateBTF]

Im not aware of anyone having issues with them. What kind of issues are you having? Idling high, misfires, etc?

The headers shouldnt make a big enough difference it would warrant supporting mods to make it run right.

I have a rolling idle up and down. I have replaced injectors, New Motorcraft EGR,MAF,Fuel pump,FPS as well FTPS,Purge Solenoid,Canister,New PCV, Crank and camshaft sensor and Both upstream 02’s replaced twice now. Still Getting P02198 Rich also P0300 Misfires 1,3,5,6 New coil as well. Tried spraying at cool start up around intake, as all intake seals replaced when installed Bosch injectors. Is there a common vacuum leak or a pinpoint location the plastic intake can crack to focus on. Next step smoke machine. I forgot to mention New Cats have very little run time. As watching my 02 sensors on test drive start out at 6.50 then work their way up to 9.00-9.50 rich out. Fuel trims upwards of -25 then they all zero out go to limp/default. PCM was tested out run through live simulator and updated software as well check out good and sealed up. Real PITA

If you clear the code and the misfire code appears very quickly then suspect the injectors
New out of the box injectors can be bad
Does your fuel smell of oil?

A misfire code that appears quickly is usually an injector
The computer cannot detect which cylinders are misfiring through the ignition, it takes several drive cycles. But a misfiring injector it can detect right away

If you clear the code and the misfire code appears very quickly then suspect the injectors
New out of the box injectors can be bad
Does your fuel smell of oil?

A misfire code that appears quickly is usually an injector
The computer cannot detect which cylinders are misfiring through the ignition, it takes several drive cycles. But a misfiring injector it can detect right away

That is a possibility as with so many counterfeit parts out there like Bosch etc knock offs. As i did buy from a reputable supplier granted like you said still could be bad right out of the box. The Motorcraft plug wires have low hour run time but i’m going to buy new NGK or Accell wires to rule out. Thanks for your help, as i have put in many many countless hours on my build up.

 

[Explorer2010fabricateBTF]

I have a rolling idle up and down. I have replaced injectors, New Motorcraft EGR,MAF,Fuel pump,FPS as well FTPS,Purge Solenoid,Canister,New PCV, Crank and camshaft sensor and Both upstream 02’s replaced twice now. Still Getting P02198 Rich also P0300 Misfires 1,3,5,6 New coil as well. Tried spraying at cool start up around intake, as all intake seals replaced when installed Bosch injectors. Is there a common vacuum leak or a pinpoint location the plastic intake can crack to focus on. Next step smoke machine. I forgot to mention New Cats have very little run time. As watching my 02 sensors on test drive start out at 6.50 then work their way up to 9.00-9.50 rich out. Fuel trims upwards of -25 then they all zero out go to limp/default. PCM was tested out run through live simulator and updated software as well check out good and sealed up. Real PITA



That is a possibility as with so many counterfeit parts out there like Bosch etc knock offs. As i did buy from a reputable supplier granted like you said still could be bad right out of the box. The Motorcraft plug wires have low hour run time but i’m going to buy new NGK or Accell wires to rule out. Thanks for your help, as i have put in many many countless hours on my build up.

 

[Explorer2010fabricateBTF]

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It has come a long ways from the start. Now just to be able to drive. Lol

 

[C420sailor]

Check for hoses in vicinity of intake collapsing under vacuum. I had that happen from an old, soft hose and it caused a cycling idle

 

[Explorer2010fabricateBTF]

Check for hoses in vicinity of intake collapsing under vacuum. I had that happen from an old, soft hose and it caused a cycling idle

I will check the Vacuum lines hoses. As i inspected the bundle that runs from EGR to under intake to then out to top left hand side of upper intake. As i know my old original engine the red line was very brittle as it actually snapped. But this new bundle i added an additional layer of protection with flex loom over the top of the factory loom as cautionary per say. I will look over again. Thanks.

 

[410Fortune]

Beautiful work!
Does oil smell of fuel?
Instead of buying more parts test the parts you have

Can listen to the injectors click
Can check spark at each plug
If you goose the throttle and then shut it off pull the spark plugs and have a look at them.. read the tips

The computer is trying to lean it out and is unable
Misfires on 4 of your 6 cylinders something is fishy or very wrong imo