Lumpy Engine & Wheel Nuts.

[2000_MPI]

Hi All,
I have a few things that I hope someone might help me with.

The first one is that my engine seems a bit lumpy below 2000 rpm in low or high gears, feels like a slight misfire, over 2000 rpm she runs smoothly. New plugs fitted recently, leads seem fine but can't see it being them as she runs fine over 2000 rpm, any ideas anyone?

The second is, has anyone found a decent looking alternative to the dopey, odd sized, Rover fitted wheel nuts (11/16 with the chrome caps, weird size if the caps are missing). Does anyone know if the CN5 nut sold by mini spares would be a good alternative?

Dave T.

[DaveC]

Dave, I will see what I can find out for you

[DaveC]

Not sure if this helps, but I got this reply elsewhere:

"The MPI has a weird diff which keeps the revs down at 70mph. The flip side of this is that it really doesn't like running at less than 2000rpm. I'd say it's quite normal, you just need to be in a low gear when going slowly and you need to be doing at least 40mph to be in 4th."

[2000_MPI]

Cheers Dave,

But I think it might be engine related as it's lumpy even when its not moving,
if you slowley rev it up, she seems to smooth out at about 2K rpm.
I will have to do a bit more Investigating under the bonnet.


Dave T

[Billy]

How's the air filter?

[2000_MPI]

Hi Billy,

I changed it 3 weeks ago.


Dave T.

[woody]

Sounds like a misfire.Put the old plugs back in and see.

[2000_MPI]

Hi Woody,

The old ones went in the bin the day i bought the car, but i do remember that this problem was the reason i changed them.

Am thinking of making up a set of wheel nuts for the car, does anyone know what the thread size is?


Dave T.

[The Marcos Graveyard]

The thread is 3/8" UNF, I'm not sure of the taper, I think it is 60 degrees.

[woody]

Try removing leads one at a time at idel to see if its one cylinder or all.If its not lead or plug your into coilpack or ecu.
Try this link for nuts
http://www.speedgenie.co.uk/avonbar/wheels3.html

[GTM Coupe]

It sounds very like a coil pack breakdown, quite common on new cars using this system, heat and vibration are killers on them, if it is missfiring/lumpy at idle but relieves itself under throttle responce then it will be the coil pack. If you can borrow someone else's that is known to be working and try it first but I'm pretty sure by your description that this is the problem.

[2000_MPI]

Hi All,

Thanks for all the replies, I have changed the leads, but no change.
Looks like it could be the coil pack GTM Coupe.
Not running too bad at the moment so i don't think i will rush out to buy one just yet.

Dave T.

[GTM Coupe]

Running with the faulty coil pack shouldn't cause any real problems but it would be something to change in the not too distant future.