Misfire/Hesitation 98 cobra

[Tx_red_gt]

Hello everyone new to svtp and hope to get some good advice and be a part of the community. i have been trying to get this car running right for the longest time now and i dont know where else to turn. Its a 2002 gt with a 98 32v swapped in But running with 01 cobra PCM/Harness so it has 01 valve covers/ignition system. MMR 4.75 9.5:1 the b heads have been ported and polished and i have deleted the irmc's, replaced plugs, new msd coils, 02's , new MAF (98 cobra) 42# injectors and new fuel pump 373s. The car runs rough and feels like it doesnt make the power it should.(felt faster with bone stock 98 engine) shakes a little at idle and has a hesitation at WOT above 4000rpm and occaisonally changes exaughst tone randomly on the high way then goes back to normal. Runs rich. no codes set either.could this be a problem with the tuning alone? I hope to fix it soon to finally boost it. Thank you all in advance

 

[Sluggie24]

Did you have a dyno tune done to it after all the work was done? If not that's where you need to start. It will either fix your issues or reveal what is causing the problem.

 

[Tx_red_gt]

Did you have a dyno tune done to it after all the work was done? If not that's where you need to start. It will either fix your issues or reveal what is causing the problem.

It has been tuned but not on a dyno. maybe my tuner is not very good. Another thing is the return fuel line is plugged at the fuel rail. Could this be causing the issue? Only 276kpa of frp at idle

 

[Sluggie24]

The only way to accurately tune a car is either on a dyno or with numerous data logged tune revisions. If you just had a tune made for your combination of parts then it's possible that tune was only to make the car drivable till it can get properly tuned.

I would recommend fixing your fuel issue first and then bringing the car to a dyno tuner.