Delta DSB0812H fan slow problem

All the above is normal , except 2000rpm is a little high at idle . can be adjusted down to 1500rpm. the computer adjusts the engine speed . in drive the transmission loads up the engine idle drops to 1000rpm . in park engine unloaded rpm increase all normal.

Check your air filter and spray clean MAF sensor.

Not likely. 20W-50 is usually used in high rpm engines in warm to hot climate. By any chance is your windshield defroster on? When the defroster is blowing your air conditioner compressor is engaged which pulls the moisture out of the air so you get HOT DRY air blowing on the interior of your windshield

A Cooling pad will do very little if your fan is already clogged up, Try blowing compressed air into the exhaust port of the laptop to free it up, Do not blow compressed air into the fan blades causing it to spin fast, this will cause damage to the cooling fan, short bursts of air into the heat-sink fins should be enough to dislodge most of the dust. if you find you're using it on a bed or on your lap where you're blocking the bottom of the machine, consider getting a cooling pad.

Cans of compressed air can be purchased at computer stores and other specialty shops, it shouldn't be too hard to find, and is not expensive.

Very possibly a vacuum issue. Maybe a line that needs vacuum for the trans is on an inlet that effects the throttle. Not sure how old your vehicle is.

Tell me when you speed up is the heater set on hot and high speed?????
WHEN you slow down is the fan still going at the same speed or dose it go very slow when on idle.
If the Fan stays on high but runs cold when going about 80 in top but when you speed up it gets hot and then back off slightly then its sounds like Water pump isent pumping the water around the engine correctly ,but then it should make the engine run overheated.or it could be a slipping fanbelt, but then that should make the Alternator to make a noise,so {throttle to 2000 rpm from idle standind still} and see if there's a noise coming from the water pump area.
The belt should have just a little free movement more on the longest part of the belt(a very little about 1/8' movement
So check it out and let ne know how you get on .
Ron

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.

is the motor hot to the touch? does it shut off while running?
You may have a bad running capacitor? for this motor
or you may have a 825 rpm motor that seems slow and is normal,compared to 1075 rpm?

fazsoliz: If the A/C system is not properly charged, it will not cool properly. Usually it is noticed at low speeds because the compressor is turning slower. If you bring the RPM up, you would probably notice it would start to cool a little better.
HOWEVER, there is a danger if the system has been over charged and you do not have enough air flowing over the condenser to keep the head pressures down. The hotter it is outside and the more overcharged the system, the higher the pressures will be in the system. They can reach dangerously high pressures in excess of 300 psi. This can cause hoses to blow, a/c evaporators and condensers to fail and compressors to fail.
If the refrigerant is contaminated or if the system had been opened and had not been properly evacuated before charging, it could have moisture in it as well as air.
The fan which is driven by the engine is attached by a viscus coupling (designed to offer more resistance as it gets hotter, thus making the fan turn closer the the engine's rpm's). If this part is not working properly, it will not make the fan turn fast enough at slow speeds to draw the air over the a/c condenser and radiator.
I have found in very hot climates, that installing an electric fan in place of the engine driven fan made a vast improvement on the performance of the a/c at idle and low speeds. I have an old Mercedes diesel wagon which I converted from R-12 to 134-A.
The a/c would freeze you out on the highway, but you would be better off rolling the windows down in town. I removed the engine driven fan and installed an electric fan. Now the a/c will freeze you out at low speeds if you bring the rpm up to 1100, but is cold enough even at 700 rpm.
You must also check for any type of debris caught up in the a/c condenser. The more trash accumulated in the fins, the more difficulty it will have in dissipating heat. The fan schroud also must be on the radiator, otherwise the fan will have little effect in pulling
air over the condenser.
Also, put the system on recirculate after a minute or so. This way you will be cooling the air in the cabin and slowly bringing the temperature if the cabin air down and not having to fight the need to constantly cool hot air coming in from the intake vent.
I hope that what I have offeref for suggestions will help you.

get a can of throttle body cleaner and spray the intake realy good also remove the mass airflow sonsor in between the air box and the intake blow it out with an air compressor this should fix the problem