If anyone might offer help, I'd sure appreciate it....

I've been plagued with a series of problems with my 1997 Discovery....Had it 8 months and it has been down 6 of those...

Finally had it running again - idle was high in N, (automatic) but it ran fine...

For some reason, while tinkering under the hood with engine running - I pulled the connector off the MAF, then plugged it back in to see if it would affect the idle....

Now I can't get the land rover to run - it starts - does have a lower idle - but cuts out when accelerating from a stop - also cuts out while driving at highway speeds....cuts out, kicks back in - almost feels like tranny or engine is disengaging....

Check engine light is on...

I've disconnected the battery - a few times to see if it would reset....

Tried checking codes at local auto store - they pulled two readings one showed VW, the other Acura - doubt they are of any use....

Could I have damaged the MAF by unplugging it, and plugging it back in?

Thoughts, or suggestions would sure be appreciated...

Thanks in advance,
Dan

 

Where are you located?

From what you describe.......whoever read your codes is an idiot.
Go buy a code scanner. You will always need it. I don't care how much you spend, just make sure it can read and erase codes. The CEL isn't going away until you erase the code with a scanner.

Now, on to the issue. If the MAF was bad I doubt you would be able to get it up to highway speeds. What you are describing sounds like an open spot in the TPS in that it cuts out for a second and then reverts back to base value, then as you push the pedal down past the dead spot it reads again and the engine kicks back in. Don't bother going to the place that read the VW and Acura code, unless you are going there to buy a cheap scanner. Give us the codes and we will get you sorted.

 

Thanks Higgs...

Took your advice...just now picked up a reader...

Had the following codes -
P1188
P1193
P1185
P0307
P1316
P1193

CEL has been on for some time - not sure which codes would be associated with this recent problem...

I reset/erased the codes - ran the land rover around the block - CEL didn't relight - but it still has the problem - runs up to 1000-1500 then drops out to 500 - over and over....

(btw...How long does it take for a problem to throw a code, once it has been cleared)

Thanks,
Dan

 

P1188 Oxygen Sensor Heater High Resistance Upstream
P1193 Oxygen Sensor Heater Circuit Open Downstream
P1185 Oxygen Sensor Heater Circuit Open Upstream
P0307 Misfire Cylinder 7
P1316 Misfire Excessive Emissions Fault
P1193 Oxygen Sensor Heater Circuit Open Downstream

Check your fuel pressure. If you have about 35PSI with the key on proceed. If not fix it first.

I would contact Paul Grant for a used MAF and while waiting for it check all the connections for the O2's. New MAFs are available but they are $200 and are aftermarket with no track record of quality yet.

The codes will probably all wait until you start it from cold to come back, but they could come back any time until the issue is repaired.

You probably need a couple O2's, but the MAF is most likely what is causing it to drop out.

 

Some codes come back next time they happen, some others must occur on two or more "drive cycles" where engine goes thru warm up. If MAF was unplugged engine would crank, then die at about 500 rpm. The O2s must have a bad fuse or something to have so many knocked down.

 

I'm thinking maybe the O2 sensor codes were from running a heavy concentration of fuel system treatment (lucas)...

Maybe the misfire was from unplugging the MAF - it sputtered quite a bit when unplugged...then died...

As mentioned before, I cleared the codes - and will wait to see what pops up next...

BUT, Amazingly it is running normal again - I again took your advice Higgs, and looked at the TPS - removed it - looked normal - replaced it - but still had the same problem....

Then I unplugged it completely - ran the rover - runs as it should no more problems...

So basically it runs fine with the TPS unplugged ???

I am assuming the TPS is bad? Will it hurt the rover driving without it, until I replace it?

Thanks again,
Dan

 

The TPS unplugged will run to about 1700 rpm, so yes, you could limp around. It defaults to a preset angle of the throttle butteryfly valve disk.

 

If truck continued to run with maf unplugged it's not working. If it died when you unplugged maf it's likely working. You can run truck with maf unplugged (rich as hell) but like I said it will die if you unplug it.

First check is fuel pressure. Cheap and easy
Something else to think about is VSS (vehicle speed sensor) will cause vehicle to coast and or sputter even if you're excellerating. You may be going 35 but ECU thinks you're going 135 and it cuts off power much like a governer.

With that said a wonky idle can be TPS, sticky throttle, or MAF is reading it's taking in more air than it actually is.

Hard start issues when you have battery power is very often related to fuel pump and or if it has been sitting for a while bad gasoline.

I would check fuel pressure, drive it around some more see what codes come back. Do some diagnosing based on that. Throwing parts at it can be expensive.

 

It will run with the MAF unplugged, it will hesitate when you try and accelerate because the ECU will need to use only the data from the other sensors to determine how much fuel you need.
I cleaned my throttle body a few weeks ago and forgot to plug the MAF back in, I drove to work, truck hesitated when accelerating, drove home, same thing.
Plugged it back in once home.
Even at 65mph it ran fine until I climbed a hill or took off from the stop light at the end of the exit ramp.
36 miles and no CEL.

EDIT:I need to clarify, it will run with the MAF unplugged as long and everything else is working correctly, like the O2's, coolant temp sensor, TPS, etc.

 

36 miles no CEL..

5 MPG