Advice from plenum spacer users

[Daisyduke]

Hi all. 

 

Fitted a second hand plenum spacer today. Also sprayed up the plenum and TB and cleaned it all.

 

Just wondered if anyone has experienced greater engine braking?

Most noticeable with cruise control on to me going down slight hills. Car feels like it holds back when overspending then catches up then brakes then catches up. Over and over. 

 

Anyone else have this or am I experiencing another fault?

Edited August 16, 2018 by Daisyduke
Silly typos

[longsh07]

Had a plenum spacer fitted for years now and not noticed any issue with cruise control and engine braking. To my knowledge the car doesn't use the brake at all when cruise control is on and going down hill, mine just backs off the throttle a little until the speed falls again then 'catches' it at the set speed. Maybe that the system works differently on UK/Import or different years?

Mines an 05 GT4.

 

Edit: May have misunderstood what you mean. When you say brake, do you mean engine braking or brake brakes when using cruise control?

Edited August 17, 2018 by longsh07

[Daisyduke]

I Mean engine braking.

Going to remove and refit as I think I may have a vac leak. 

 

Mines an 05 gt

[longsh07]

OK, I'm with you now. For me, the car holds its set speed on a flat road or uphill. Downhill it backs off until speed drops then catches the car at the set speed once things level out. This was the same before and after fitting plenum spacer.

If its not a vac leak then its possible something was dislodged when cleaning which is now effecting the throttle.

I'm sure you know but either fully disconnect throttle body or the battery before moving the butterfly valve.

Good luck, hope you get it sorted