Ok guys I have a 2005 Mustang GT with a ProCharger Set up in shop. It originally came in with a fuel pressure issue, we upgraded to the GT500 fuel pump set up and it got rid of the fuel pressure issue but in turn revealed another issue all together. Returned the car back to stock, removed Procharger, installed stock intake, stock injectors. Was also throwing a code for a faulty computer so that was also replaced with new and flashed for the car, also replaced the throttle body with stock and MAF sensor and MAF pigtail also replaced O2 sensors. Whenever the car is at part throttle (2500-3000RPM it breaks up badly) Deleted the Intake runners, tuned for the delete with SCT and also worked with Second Street to get this issue resolved.
STILL NOT RESOLVED.
Tests performed are as followed:
Compression test
Leak down Test
Running Compression Test
Coil on plug test (multiple times)
Pulled the Harmonic Balancer checked the reluctor ring for damage
Smoked tested multiple times
vacuum tested multiple times
Pulled Valve covers checked for broken springs
Checked all grounds
As of right now the car only has upgraded fuel pump, intake runner delete, and shorty headers.
Car only has 40,000 MILES on it.
Called other shops for insight no help or resolve.
Any one out there have the same issue or had the same issue and fixed it????

 

How old is the fuel filter?

 

Timinig maybe as in bad Cam Phaser or Cam Phaser Solenoid? Since they change timing based on engine RPM that's the only thing I can think of. Right at that 2500 to 3500 RPM would be where the solenoid gets flakey or the cam Phaser isn't adjusting correctly.

 

A good tuner would be able to rule out tuning issues.

The basic things that would cause what you are describing are issues with fuel, spark, or timing. The other thing not listed in that equation is installing the delete plates.

Check for CELs

I would confirm it is on a good tune.

Check the wiring from the fuel pumps to ensure everything is grounded and ran with the proper gauge wire.


Check the charging system, batt and ALT.

Inspect the cam phasers.

Ensure all vacuum lines are engaged and also take a reading of vacuum.

Take is to ta shop that knows what they are doing.

 

All, I think the OP IS the shop asking for help.

 

Thank you, I am Posting from a shop and have been in contact with several other shops regarding the issues that this car has. The fuel filter, spark plugs and COB plugs are new and gapped properly.. The timing sounds like something to consider. Thank you all for your insight

 

Timing issues can also be related to oil pressure in these cars.

http://www3.jasperengines.com/blog/2...l-pump-update/

Note the RPM the OEM pump starts to bleed out pressure...

 

I'm curious OP, any updates on the problem with the car?

 

Well, Still no resolution, waiting on a gas pedal assembly to come in and see if that resolves anything. Did find out that there were stereo components that were wired on top of the PCM which could cause Electrical noise.

 

Any updates on this one?