When you add long tube headders you in essence push the 02 sensor further away from the cylinders plus you change the way the engine scavenges plus you give the ECU an improperly timed sample to go by resulting in a leaner and cooler exhaust reading so the engine is going to run with a higher idle because it cant add enough fuel to run right and goes into LIMP MODE and thats why your tps is reading whacky because the idle sets at an rpm that will get the car home or off the road......Sometimes it works in reverse and causes plug fouling too when the IAC isnt functioning correctly...
To fix the problem you need to add an adjustable fuel regulator and bump up the fuel pressure a few pounds and also wrap your hedders to keep the exhaust as hot as possible plus to add there are 02 sensors you can buy that are made for long tube hedder use too which is usually done by simply upgrading to 4 wire 02 sensors and wiring in the extra heater circuit wire ,,...
The right way is getting Ford Racing 24 lb injectors and running the X3Z computer or getting a chip..The MAF's are the same..
Another problem will be running issues when driving in rain....I got sick of the issues and just installed shorty hedders and I also wrapped those too...
Good Luck