Bit of an odd one really,

I fitted a Walbro 255lph pump on Sunday, everything went together ok and the car fired up first time.

The problem is, on cold start it now idles from 1600-900 rpm for a about 5 seconds then settles back up to 1600 rpm until warm like usual. No warning light or anything comes on.

Anyone have any ideas?

 

ive just had one fitted along side a PFC and Denso plugs. I get simaler probs when cold. Thought it might be the water temp sensor. But now im wondering if its the pump.

 

Give the idle control valve a clean with carb/brake cleaner it worked for me.

 

Tried that and also replaced the MAF. Still no luck.

 

i know this sounds stupid, but i had an issue with my thermostat. i didnt have anti freeze in my system and during the BIG FREEZE this must have fu*ked up my thermostat which was causing my engine to do all sorts of weird and wounderful things. replaced with a zero sports thermo cool thermostat and it seems to have corrected many idling issues