Cold days 94 f-150 high rpm start

Check the air intake sensors, called MAF or MASS air flow. They have temp and baro devices in them.

This sounds like the RPM may be a little high, but normal operation is called a "cold start routine". Like the old fashion Choke, the "cold start routine" is suppose to increase the RPM for several minutes and then decrease to running idle speed. This will engage in each "cold" start, but not on a warm engine. It is designed to do this.

Usually when an engine runs higher RPM than it is set for, it means extra air is entering the engine from somewhere. Using a spray water filled bottle, go around seams and also spray vacuum lines and the EGR pod while the engine is running. Any openings will draw in the water and affect RPM. Then you will have found the leak.

Now you can look up you exact engine on the Web and find out 2 things. If it has a 2 piece intake manifold and if it has intake Manifold runners. The 2 piece design often failed when the gasket holding the 2 halves started dissolving. The intake runners, could stick out of position and make RPM higher.

Now aside from these 2 items, you might get a Code showing that the engine is running lean. This would actually not be showing the lack of fuel, but the overabundance of air coming from the leaks.

R u start the car in cold morning or any cold condition? If so, it is normal revs up itself. Sometimes I see some cars revs up to 2000 rpm for 2 to 5 mins, then drop down to 1000 rpm.

They make a connector for the sender unit and they have to usually be replaced. Watch which way it goes on since they are a little cumbersome plugging back on...I prefer soldering the new connectors on too.

Sounds like a coolant sensor problem. It signals the ECU for open loop, cold start rich, high idle, until warm up is reached.

when motor cold it will rev up around 2000 then drope down

it will idle high with air con on and revs will go up and down try turning air con off it that fixes it then there is no problem

I would agree.

Here is the most common cause of surges and stalls and low idle, it is the idle speed control air-bypass valve and throttle valve (IAC for short), they get full of gunk over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake

check the anti-freeze level in rad if *** is low in the rad it will cause this , in the raditor not the fill bottle as sometimes the fill bottle will be full ,***** be sure to do this with the engine cool and motor off