Leone stumbling.

[Starlite]

Hello this problem have been around since i got my leone 89 mpfi.

When i driving in 1 gear low speed the car stumbling like pressing the gas pedal up and down several times.

Or like holding speed steady and there is a lash somewhere.

Its very annoying and impossible to hold a steady speed when the car twitching and stumbling.

 

I have read about this somewhere else and its a common problem if i remember corectly.

[jsyme]

Painful.  

 

My first take is spark plugs or engine "missing" as in a timing miss. 

Maybe it's not timed correctly for your elevation. Mark it, Loosen and adjust the distributor and see if it improves at idle going +/- 15 degrees and then return it to your mark.

Next check all your spark plugs.  Have they ever been replaced? are they missing ceramic on the plug itself?

Next consider replacing the spark plug wires themselves, there should be 5 1 to the coil, and one to each spark plug. was one loose anywhere?  is your distributor cracked or corroded beyond recognition inside? A new cap and rotor are easy to do and will make a substantial difference!

Get some emery cloth and clean up all 5 contacts and then put it in your emergency car parts with the car so when you're stuck you have one with which to limp back to town.

 

Next maybe a plugged fuel filter - easy to swap. Location: Right on top of the USA driver side strut tower - black inline filter about half the size of a coke can.

 

Let me know when it purrs again. I'd like to know.

[robm]

I must respectfully disagree with jsyme's ideas on this.

 

1. Sweden is high latitude, not high altitude.  Stock timing.should work fine.

 

2. Bad plugs and wires should show up under heavy load, not when trying to maintain a low speed in first gear.  Changing them is cheap(ish), and can't hurt, but I would not expect this to fix the problem. 

 

3.  The same can be said for the fuel filter.  Plugged fuel filters typically supply enough fuel for low speed, low load, and only show up when trying to accelerate or go fast, which doesn't seem to be a problem.

 

I do not know much about the MPFI.  Could it be a sticky IAC (Idle air control) that causes the stumbling by jumping between too wide open to too closed?  No,apparently,  MPFI's don't have such things, according to info on USMB. 

 

Do a search on this site for MPFI AAV  and IAC.  It looks like Grossgary has lots of expertise on this system.