Good morning I have a 2000 impreza p1 just recently I've noticed on idle a plopping noise coming from the exhaust it happens every time the car is idling but it's not got a pattern to it. I've recently changed the spark plugs it started happening about 500 miles after I changed them I've checked the tightness of these and they are fine. On part and full throttle the car is fine it just seems to happen on idle and when the car is warm any advice would be much appreciated also no engine lights are on. And I'm running a syvecs ecu if that help thanks mike

 

Sounds like a misfire. Check the condition of the plugs and also the soil packs.

 

Checked the plugs and replaced with my old plugs that were fine in the car and still the same going to get a compression test and a leak down test done to make sure nothing untoward is going on inside

 

Didn't want to suggest that just yet but mine did it on a cold start and wasn't the sound you hear when you have pops and bangs. It was a blown engine.

The P1s tend to need a rebuild at 70k reason from what I have heard is that from the factory they had a really aggressive map and with our fuel not being up to the same octane rating as Japan what they did was put something on the fuel filter/pump. It degrades over time and becomes non existent causing loads of det.

 

Mine is more when it's hot also mine is fully forged 2.1 closed deck block running a syvecs ecu rcm fuel pump. Just thought it could be a valve hasn't really lost performance but I am driving it like miss daisy until I find out the problem

 

Might be worth letting Thwaites have a look at it.

 

They had it today dave y not 100% sure what it is atm did a compression test and it was fine he told me to get the injectors checked go through my earth's and vacuum lines also my alternator wasn't giving out much power so I'm changing that so fingers crossed I will sort it with one of these

 

Injectors can be noisy and its a clicking sound that they make. You said it was coming from the exhaust are there any leaks.

 

All sorted now my alternator wasnt really charging the battery when we checked it running it was 12.6 volts which in turn was obviously not enough to run the injectors properly and the fuel pump changed to a good alternator and the car is perfect again

 

Great stuff glad you sorted it and passed the info on.

 

Good you got it sorted mate