I just purchased this vehicle so I'm not too sure on the history. It seems fairly well maintained, the air filter is clean, cap and wires look new. I haven't pulled the plugs to check them yet but I'm hoping they were replaced with the cap and wires.

My 95 3.9 Discovery has intermittent starting issues. It starts fine when cold, occasionally after it's warmed up it will fail to start. When it fails I let it sit for a few minutes and it starts up a bit sluggish but is fine after a few seconds.

Today after driving around 60mph for 15 minutes I stopped at a red light. It idled fine, but when I started to accelerate it almost stalled. I let off the gas then lightly applied the pedal and it sped up - a bit sluggish. 1/4 mile later I turned and tried to accelerate and it stalled. I pulled over, waited 2-3 minutes and was able to get it started. It seemed to run fine the rest of my trip to work (5 minute drive from there).

For the most part it seems to drive and idle OK for a car with 130k miles on it; this is the first time I've had it over 45 mph for any length of time. My initial digging online points to injectors or a possible issue with the ignition amp module, I was hoping to get some opinions from some more experienced rovers that may have dealt with this type of issue before.

A minor secondary concern, the tach is stuck at 1750 rpms. Does the '95 tach work off the alternator? Is the tach likely bad as it doesn't ever move?

Thanks!

 

You don't metion any codes........
I have recently posted about a similar issue. If you have time search and read them and the advise I got. What seems to have solved the problem was a good seafoam cleaning of the intake system and cleaning the idle valve. Of course I had already ruled out cables and spark plugs, all new.

 

I've been meaning to check those codes, just ran out and found it:

Code 14 - Coolant sensorUsually indicates a bad fuel injection coolant sensor. May also indicate a bad engine thermostat or a stuck viscous fan clutch. Refer to test 14, continuity test procedure.

 

Tach most likely toast. There is a "flying lead" that plugs into the back of the alternator (not bolted down). This provides pulses that the tach counts to display. If tach were reading zero, it would indicate alternator dead. Perhaps your wire is off or not attached properly.

If you have not done so, the whole factory set of owners and shop manuals, called the RAVE, is a free download below.

 

so there is an ECT - Engine coolant temp sensor and an EFT - Engine fuel temp sensor.
the coolant sensor is $20, the fuel sensor is $150

after doing a search for code 14 thermistor instead of that "fuel injection coolant sensor" that doesn't exist I think I've narrowed it down to the coolant temp sensor and will get one ordered.

 

And there is probably a gauge sensor as well. On my D1 they are side by side, the gauge one has a single wire, and the coolant temp sensor that reports to the ECU has a two wire connector on top. Comes out when engine is cool or cold with minimal coolant loss. Hope your connector is on tight, not covered with green corrosion, etc. Mine is just beside the thermostat and upper hose connection, driver's side.