Hesitation and back fire through throttle bodies at 2000 rpm

[turbomrk]

Pull the MAP sensor christmas tree fitting where all the lines connect to and make sure and certain that each port is open and are not blocked or restricted, do the same for each for the vacuum hoses and where they connect on the t/bodies. If you have a restriction or partial blockage in the vacuum circuit you will get wierd running and misfiring.
If that check out then you need to run it up with Tune ECU and check the throttle balance and ISCV settings.

One more thing to check is when the engine is running switch over to the map and watch what the TPS % value when you just start to see RPM increasing as you just move the throttle slightly, you might have to lift your static TPS setting slightly to match throttle movement with TPS movement. Like mine was jumping all over the place at 1% throttle was bouncing between O and 3% on the TPS and ran like a pig until I replaced the TPS. YOu could also have a TPS that might be out of phase or sync at the RPM you indicated.

Hope some of that makes sense and helps>

Thank you John you were a big help resetting the ISCV and TPS cured the both problems. Thank you again!

 

[John Miller]

One last thing to check is with the engine off, ignition on and Tune ECU connected, check that your TPS is actually going from 0% to 100% and back to 0% when released.

It means that your engine mapping and AFR will be way out when you are at WOT (and elsewhere) if you are not getting 100% on the TPS when the throttle hits the stop.

If the TPS does not reach 100% at WOT the only way you can adjust it is to lift the static .60V setting on the TPS, mechanical adjustment of the throttle cables etc will not lift the TPS value any higher because the throttle shaft has reached it's limit of travel. Lifting the static TPS setting by .60V +.02V should raise the total TPS travel by around 1%.

Happy tuning