Hi guys,
Need some advice please. When starting my 1995 wrx from cold it struggles to rev/tick over for approx.30 seconds then seems to clear itself and revs up to 2000rpm then as it warms up slowly drops too around 1000rpm. I don't know if this is down to the fact that it dont get used much. (to work on monday, back home friday. The joys of been a hgv driver.)

Any help or advice would be appreciated
thanks in advance.

 

This could be 2 things off hand, first is the maf sensor and the second is the coolant temp sensor failing, either way they will get worse, you need to do a diagnostic on your car, dealer equipment is better than most of the other techniques and then a technician to check for any other issues, but its up to you.

Tony

 

I had the same sort of thing as you, the fuel i was using was tesco super,
i switched to shell and it seems to have helped,
This came after trying many different sensors but nothing was helping.

 

Thats funny as it's on tesco super now due to the fact i pass by on my home on a friday,used to run it on v power all the time shall have to start filling up on a sunday with v power see if it makes a difference.

 

Did you find it helped at all.

 

Tesco petrol gets my CEL to flash .... Knock Sensor is the reported fault - it remains off when using other petrol.

Will not touch Tesco petrol .... don't care if it is £105 with the 5p a litre off offer!

 

Very likely to be cracked coil packs.

Mine did the same.

 

Have had the opposite, poor shell topped up by good Tesco. From what you have put the factor could be the forecourt you are using, if their tanks are dirty then that will cause issues. Hence moving to another garage with clean tanks whether it is Tesco or Shell will show a improvement.
Last re-map to 416 bhp on tesco 99.

 

mine did exactly the same(1993 wrx) struggled when cold and reved to 2000 then back to 1000 repeatedly til warm then was 100% ok turned out to be the coolant sensor

 

i had this issue when i used tesco 99 ron. i tried all sorts including a new coolant temp sensor. then i tried v power/optimax and the problem has never come back. the problem with tesco 99ron is the high ethanol content. it doesnt work well in cold weather.

 

edit, i ve just fitted a z4 ecu to replace my w6, so i might try tesco 99 again to see if the z4 copes better.