f250 2003 runs bad after it temp.gets 185 cold its ok?

Answer 1

Hmm, taking a stab at this since there's little info to go on. Without knowing anything else I'd have to steer in the direction of oil pressure. Even in a very worn out motor, main and rod bearings and cylinder walls, the oil pressure looks normal when it is cold and as it warms the pressure drops substantially since the heat thins the oil and it runs through the worn out main and road bearings faster than the oil pump can keep up.
The hot pistons will start to drag on the cylinder walls if the oil pressure is really low and bog down the motor. It's not too difficult to check the oil pressure. Some cars have a oil pressure gauge that is usually an OK means of knowing whether you are in the normal or low range. Some just have a red light that tells you it's too low but not how low. You can buy an oil pressure gauge, hand held, and remove the oil pressure sensor from the block and screw it in. Then start the motor and watch the pressure readings. It will read high when the oil is cold and after the motor gets hot it should level off at around 30-35 PSI if your main and rod bearing are in good shape. If it drops to around 5-10 PSI then you are barely scraping by and need to consider an over haul or swap out the motor with a rebuilt. I've seen motors still run on just 3-5 PSI but their just waiting to spin a bearing or lock up a piston in a cylinder.

Good Luck!

Answer 2

Assuming the temp guage is accurate, you could have a bad gasget that is leaking when you reach normal operating pressure in you coolant system.

Best thing to do is hook up to the computer and read the error codes with a scan tool.