Throttle Hesitation

[rojer386]

Good afternoon all.

I was out in 189 recently and while it was not fully warm I had hesitation when accelerating. Not like a misfire but a lull in acceleration for about a second or two when pressing the throttle pedal. That along with it smells like it is running slightly rich, my initial thoughts were lambda sensors. No lights on the dash...yet!

Also, during that drive, when I returned to the car and went to start it, the immobiliser light stayed illuminated (can't recall if it was flashing or not) and the car wouldn't start. Switched off and tried again and she fired up?

Any ideas guys?

Many thanks

B

 

[James__H]

I have a flat spot around 3000 rpm from cold. When warmed up - no problem.

I don't believe this is unusual? If anything, it shows the car hasn't been remapped, which in my mind is a good thing.

 

[photo_ed]

I have a flat spot around 3000 rpm from cold. When warmed up - no problem.

I don't believe this is unusual? If anything, it shows the car hasn't been remapped, which in my mind is a good thing.

Interesting. Personally never known my 1*2’s to display any kind of flat spot, cold or otherwise. The F4R in its next incarnation in the 197, definitely had an issue with this, and it affects some 200’s too by all accounts, but I have a sneaking suspicion that’s down to folk putting shite fuel in them.

172 & 182 power delivery has always been for me linear with a moderate build noticeable at between 4.5-5k.

I wonder if OP has the beginnings of either an ignition fault (coil pack?) or fuelling issue (more than likely an injector on the way).

 

[Big Dave]

My Trophy had the flat spot when cold around the 3k mark..

I was going to fit a RS tuner map on the car, but never did..

I had been told this map would've removed the flat spot, and add drivability..

 

[hoolio]

Take your pick of reasons for this, there are a fair few threads with a similar theme but sticky/dirty throttle body, injectors, coil pack, crappy old fuel, was there also something of an issue with the contacts on the throttle peddle Itself? Hopefully it is nothing though.