Hi i just had cards rebuilt and now throttle will ether stay at 4000rpm or is really slow to idle down got any ieas

Try cleaning the throttle plate and the IAC - idle air control passage . There are videos on youtube showing how to do these cleanings How to Clean Throttle Body and Idle Air Control IAC Valve Quick and Easy

clean throttle body really good, remove Idle air control to see if it is plugged with carbon deposits, (IAC). Also a vacuum leak will cause this too. Depending on vehicle, the Idle air control should be on or near throttle body. God-Bless!

ARE THE CLAMPS LOOSE WERE THE CARBS CONNECT TO THE ENGINE

the ECU is messed up or the Throttle body is clogged.

I would try a new throttle position sensor. Yours must be giving a wrong reading.

Only Info I see is "Homelite Chain Saws" - not much to go on.
Most saws have two carb adjustment screws, Hi, and Lo.
Assuming the saw will start and run enough to warm up, then
adjust the Lo screw in, clockwise, until the motor starts to slow down,
turn only about 1/8 turn at a time. From the point where it starts to slow down, turn it out about 1/4 turn. This should give you a decent idle. Now pull the throttle, and see what happens.
A - Saw runs up to speed, but dies off, or starts to slow on it's own.
turn Hi idle screw out about 1/4 turn.
B - Saw speeds up, but runs sluggish, fat - not real hi end.
Turn Hi screw IN, about 1/8 or so, and try again, or adjust
while running at full throttle. (best way)
IF it won't run well, try turning both screws all the way in to seat them, then come back out about 1-1/2 to 2 turns. this should get you in the ballpark to set things up as above.

Once the saw is running well, adjust the idle screw to a smooth idle but slow enough that the chain stops moving.

Stay safe

Idle sensor or throttle body positioning sensor

Maybe a short to the TPS or something shorting it out. There's also the IAC that really controls the idle but usually it will cause the RPM's to go up and down a little erratic if bad. The MAF sensor can cause major problems as well but since you already swapped the TPS and it helped and then stopped I would focus on that sensor and especially it's wiring to and from the ECM. Be careful with the sensor signal wire to the ECM can blow it if more than 5v passes or spikes.

p1545 is a throttle control malfuction code

You can try to reset the throttle body by opening the hood and drivers door then turning your key to the accessory position. You will hear the throttle body whir and click. It may take up to two minutes. Afterward, the car will relearn your habit of driving and adjust accordingly.