Good Day All

I am new to forum's in general, have owned a S40 T4 2000 Automatic for the past 4 years with 172 000km, never really had any issues or problems until now.

When driving normally from standstill with part throttle up to 120 km/h the car runs fine. As soon as i reach an incline or wish to overtake on full throttle[ 100% she would kick down and start accelerate with power and then start to develope a miss ie 3000 rpm, she runs out of power but soon as i tap off to say 90% on the accelerator pedal the power is back and she will run up to any engine speed. As soon as i put pedal to the floor the lack of power is back.

No error codes, no starting problems hot or cold engine idles fine and smooth.

I have checked the spark plugs gaps are fine they seem to be firing fine

Help

Regards Short t4

 

Do you hear any spark knock (detonation)? The ecm might be pulling timing if it detects knock. Do you run premium or regular fuel?

Other issues that came to mind, running lean from a clogged fuel filter, bad TPS, clogged air filter, or simply needs new coils. Lots of guesses. Do you have any diagnostic tools? Any check engine lights?

 

What Hudini said but also could be transmission related.Try to shift back manually to 3rd before you gun it and see if the same happens.

 

Prior to this issue the fuel grade was always the same. 95 Octane Unleaded.

Theres no pinging or knocking, feels like a miss fire. What baffles me is this only occurs on full throttle, even when gearing down manually to 3rd, same story. As soon as I back off on the throttle all is well.

Could possibly be a fuel filter, due for major service soon

 

Are you running higher boost?Which plugs are you using and at what gap?Seems like a spark blow out but if you running stock boost then thats a long shot still could be a very weak spark issue.

 

That's a good thought, maybe close the gap a tiny bit, down to .023" maybe? WOT always demands all systems are operating as designed. One weak coil or hairline crack and things go south.

Changing the fuel filter cannot hurt and might just help a lean miss.

 

I had a similar problem in a 2007 s60 2.5T.
Replacing the Fuel Pump seemed to fix the majority of the problem.
Replacing the Fuel Filter probably did not hurt.
I assume the Filthy Airfilter contributed but was replaced before the problem reoccurred.

Symptoms: When heavy accelerating over 3500 RPM the engine would lose all power, it would continue to run but it was more like coasting after you hit 3500 RPM. The s60 would generate CELs though.

 

Sometimes these turbo cars have an intake tube colaspse at WOT.

 

I had this happen on 2 occasions... the first occasion was after I put a short ram intake on, and the cone fell off after driving causing the power to surge. Technically, that doesn't make sense, but the car ran fine again when I slapped it on, but I didn't have a screwdriver at the time to make it tight... so it fell off AGAIN, and my power surged out. I got home, tightened it up, ran fine ever since.

The other occasion I've had this happen is when the top hose from the intercooler collapsed under pressure... and I just now realized the guy above me said the same thing XD