sudden lag around 40

[reyvin]

Hey all.

When I nail the gas the car shifts perfectly (I've got over 90k on it, original engine, turbo, tranny...everything) but when I'm taking it easy sometimes (but not everytime) it gets real boggish and a bit jerky around 40 mph. This a tranny issue or turbo or..?
If it was the turbo, I'd think it would do it at any speed?
If it was the tranny, shouldn't it do it regardless of how I'm driving?

I know its a pretty vague description, but its the most accurate I can do without having someone in the car while I drive.

Thanks for any insights.

 

[mitch83]

it's auto right. sounds like a tranny issue to me. I dont know enough about auto trannies to make a good guess but thats what it sounds like to me. If it were the turbo it would be more of an RPM problem not a speed problem.
mitch

 

[lokmeup]

Could be phantom knock pulling your timing...

Ron

 

[reyvin]

What's phantom knock?

and yea....sorry bout that. I should have mentioned: its auto.

 

[lokmeup]

Phantom knock is false knock. Knock that is not predetination in origin, but mechanical. Like rocker tick, loose knock sensor, etc. So, when the knock sensor picks up predetination sounds true/false it pulls timing to save the engine from detination. This pulled timing feels as light as nothing or as much as a brick wall depending on how much timing the ECU is pulling.

Search for "phantom knock" on DSMTuners and DSMTalk.

Ron

 

[reyvin]

Will do, thank ya. But do you think that would make it lag at a certain speed/RPM like I described?

 

[reyvin]

Hey again Ron (or anyone else familiar),

I did a search for phantom knock. I assume its the same thing as the clackety lifters we've been 'blessed' with? Are you saying this is connected to my lag problem also?

Bottom line is: What can I do to fix these things? I've heard replacing the lifters is good...but with what? And for the lag, do I get a new (or different) knock sensor or..?

Thanks again.

 

[lokmeup]

Well, you really don't want to go start replacing parts by guessing whats wrong. You should really use a pocket logger to see if it is indeed knock, an A/F problem or something totally different.

Ron

 

[reyvin]

Where can I find one of these 'pocket loggers' and what do they typically cost? Thanks yet again!

 

[reyvin]

*bumpo*

 

[lokmeup]

google is your friend...

ron

ps. http://pocketlogger.com