Help with rough idle please!!!!!!!!!!!!!
 

Hi,
i hope people still use this website ! soo i have a 2004 monte carlo, when i bought it it was idling rough like almost misfiring but it doesnt die. the RPMs will go way down and it will start sputtering, it will also do this when im driving it and if i push the gas all the way down it wont do anything for a couple minutes and then it flings forward. I took out the IAC and cleaned it and ever since i did that now its idling way too high (but also doing the same misfire thing as before) if i put it in park it will go up to 3rpm by itself and if i'm driving and let off the gas it will stay at the speed i was going. also if i first start to drive it will go up to 50mph by itself without me even touching the gas. i had someone try to fix it and he replaced the hoses and intake gasket and changed the oil and a couple other things.. Im getting frustrated at this point and about ready to just sell it but i wanted to see if anyone else had some ideas? could spark plugs do this ?
i just ran the codes today and it came back with these
p0134
p0135
p0136
po507
some different people ive talked to said o2 sensor would not do that.. i know almost nothing about cars so go easy on me lol
when i find out everything done to the car already ill update the post..thanks in advance !
heres some videos i took

I would try a couple of things.

One, you might have ruined the IAC when you cleaned it, or it's stuck somewhere. I would just get a replacement, since they are cheap. At the same time, I would get the throttle body blade cleaned. You might have a large amount of carbon build up preventing the blade from moving correctly.

Two, unplug the MAF sensor and see if the idle dropping is fixed. If it isn't, I would get the fuel pressure tested as the regulator might be bad. You can also pull the vacuum line running to the fuel pressure regulator and see if it is wet with fuel or smells of fuel excessively.

Three, I would get the exhaust system backpressure tested. You seem to have a few issues in sensors and the car might have run too rich for too long and fouled out your catalytic.

How could you ruin it from cleaning it and how would you check if its ruined?? Ive cleaned mine before and have concerns now..

Something I found on youtube may help? try the link.

No.. Yea kinda maybe.. I have this ongoing problem with a couple other things tho and just getting all the info I can..

It's a valve on a spring with electrical connections to move the valve. There could have been damage to the electrical connections, the spring could have been bent, carbon could run off some areas and get stuck in others.

The engine should run IAC checks to tell you if it's not working correctly and throw a CEL, but for the cost of them, if it's that dirty that you need to clean it and it threw a code, then I would just replace.