Jaguar Repair: 1986 xj6 intake air temp sensor, palm desert ca, intake air temp

Question
Hello Howard My 86 xj6 is great,However I live in palm desert ca. and when the ambient air is 90 deg f. or better the car does not want to run, it act as if it is being starved of fuel, I checked the filter and pressure all is good, at night the car runs great, I've almost divorced over this problem my wife drives to and from work in the car and has been towed 3 times and I have gone to get the car about 10 times, But each time I go to the car it runs fine, But then it happened to me it becomes sluggish and will not accelerate, in fact the more you push the pedal the worse it runs. If I feather the pedal back just a little it will continue to run but with no power and loose speed constantly on a grade. any suggestions?

Answer
Hi Steve,
The air temp sensor can be tested by use of an ohm meter between pin #6 and #27 in the airflow meter. +60 deg C = .60 K ohms, +40 deg C = 1.18 K ohms, +20 deg C = 2.5 K ohms.

However, that is least likely your problem as the air temp sensor has a very small influence on the fuel mixture. The coolant temp sensor has a major influence on fuel mixture and the readings on it are, +80 deg C = .325 K ohm, +60 deg C = .60 K ohms, +40 deg C = 1.18 K ohms.

You said you tested fuel pressure. But the fuel pressure MUST be tested in the failed mode and useless info if tested when it is running ok. It must be aprox. 42 PSI (engine not running) and about 32 PSI when running. Note that some later 86 / 87 series III cars had a fuel temp sensor that controlled the pressure regulator.

Howard