Misfire in the engine. Timing has been checked and runs worse when timing is set correctly. Have checked injectors, vacuum. No problems indicated. Problem started with engine loading up and backfiring while coasting down a hill. When I pressed in the clutch to change gears engine would die. Plugs and wires have been changed in addition to the cap and rotor but did not solve the problem. Compression test was done and all cylinders were above limits. But number 3 cylinder was noticeably lower than the rest. Obviously no power and it barely makes it up a hill in 2nd gear. Any help or suggestions are appreciated.

 

Year & engine would help.

Based on what little info I have I'm guessing a gross intake leak of some sort.
If its truly a backfire.. which is highly unusual on a FI engine.... you might have a bent intake valve on #3 or the cam is out of time.

 

It's an 87 2.9 litre engine.

 

With TFI ignition systems I would change the TFI module just on speculation, they are known failure point and usually last about 10-15years in cooler climates

2.9l engine ran 9.0:1 compression ratio so should show 150-160PSI on cold test

On cold start ALL fuel injected engines should REV up to about 1,500rpm, don't touch gas pedal for starting
Then computer will drop engine RPMS down to 1,100rpms if cold or about 750 if warmed up already
Does that happen?

If it doesn't then you need to Clean IAC Valve and probably replace ECT SENSOR, ECT sensor is used by computer to get engine coolant temp(ECT)
ECT sensor has TWO wires
There is also a temp SENDER, which has just 1 wire, this is for the dash board temp gauge, totally different types of devices, sender uses 12volts, sensor 5volts so not interchangeable


After engine is warmed up and idling, unplug the the 2 wire connector on IAC Valve, engine RPMs should drop to 500 or engine may even stall, either is GOOD it means no vacuum leak
If idle doesn't change then you have a vacuum leak