//// occasional cut power but no check engine light ////

Hi All,

Because of all my reading here, it seems to be advisable to run the car hard every tank or so.

With that , yesterday , I did my Italian tune up for the tank

While I was on an uphill grade on the highway I slowed my speed down to approximately 45 miles an hour dropped it into 4th and got on it...

For whatever reason when it got to approximately 3200 RPMs it felt as though power was reduced greatly ( just a funny feeling since the acceleration pull no longer felt linear ( a brief notch as it were) so I instinctively let off the throttle ....

From what I could see while watching the ScanGauge boost reached a maximum of approximately 22.3 but went to approximately 17 or 18 pounds ...

None of this was actually sustained for any length of time because the car did accelerate pretty hard and then the power cut seemed to happen so I let off ... not abruptly tho...

For the rest of the drive home the car did not have the same responsive power as it had before my Italian tune up ... there were no check engine lights , no error codes on the scan gauge . The car was not limp mode weak but not as powerful as before the italian tune up.

This has happened several times before and the Cure always seems to be shutting the car off and restarting...

When I say the car doesn't feel as strong I'm guessing it feels 70% as strong as before until I key off then things go back to normal strong.

This has happened several times before also.

In the past I have gotten occasional error code
Which I think was the overboost code but I find it odd that I can get Cuts in power with no error codes being thrown?

Thanks in advance for any and all help

Andrew

When it happened to me it was a frozen (rust) turbo actuator. Your problem can be further diagnosed from the Low Power//Limp Mode link in my signature. Lots of issues are not monitored by the ECU, it knows what it knows. Having no stored code is a clue.

I would do some logging with vcds. That will tell you if its anything related to fuel or boost

Check turbo actuator with a vacuum pump to see if it holds vacuum or not.

JB05 said:

Check turbo actuator with a vacuum pump to see if it holds vacuum or not.

Click to expand...

^This. If the actuator is original (or close to it) with that many miles, it's a fair bet that it may not be holding vac any more. Fortunately, on an ALH turbo the actuator is replaceable separately.

The original actuator on my '02 made it to about 230K miles (I got another 100K out of the rest of the turbo before the main seals started to go); I'd say over 300K on an actuator's probably a bit above average for lifespan.

Hi

Thanks for the input ...

Hopefully this weekend I'll crawl under the car and and hook the mighty vac to the actuator and see what it does and if it holds a vacuume or not..

I guess while I'm under there I'll try moving the linkages to see if they are free or binding.

I only have a scan gauge so can only see errors and codes and not log .which knock on wood I haven't had lately...

Thanks
Andrew

Although many say that an episode of limp mode will set a code (and/or trip the CEL light) I've never had that happen and have had many a limp mode events.
In addition to the above normal common causes, a bad/or failing MAF will also cause the issue.