Misfiring? Turbo Lag? (2006 XC70)

[taylorhoyt]

I'm a high school student, so im not all too experienced with cars. However, I sometimes notice when I'm leaving my neighborhood, and I turn onto the highway and try to accelerate to 55mph (usually closer to 45mph due to a corner that's coming up), my RPM will drop for a second, and my '06 XC70 will refuse to accelerate for a short moment.

I've recently changed my spark plugs to OEM NGK plugs, replaced my mass air sensor to an OEM one, and the air filter to an OEM filter. All were bought off of FCP Euro. The car has also had a timing belt replacement recently, and has been checked fully by an experienced Volvo mechanic right after it was purchased. It has a little over 140k miles on it, and the previous owner took terrible care of it.

I'm hoping it's just turbo lag, or me just being paranoid. Any help is appreciated!

[goldxc70]

Doesn't sound like turbo lag to me.

Is it a new thing since the other work was done?

[vtl]

Can be a bad fuel pump. Need to attach DiCE/VIDA or advanced enough OBD-II tool and see if the fuel pressure deviates severely from 400 KPa while the car rejects to accelerate.

[taylorhoyt]

Doesn't sound like turbo lag to me.

Is it a new thing since the other work was done?

It was worse before the work i did. After replacing the mass air flow sensor and the air filter it became less frequent, and after changing the spark plugs (the old ones were absolutely atrocious looking), its a rare issue now, but still annoying when it happens.

[taylorhoyt]

Can be a bad fuel pump. Need to attach DiCE/VIDA or advanced enough OBD-II tool and see if the fuel pressure deviates severely from 400 KPa while the car rejects to accelerate.

I hope it's not that, but i'll likely take it to a mechanic to check it out. (Those tools are expensive!)

[vtl]

It was worse before the work i did. After replacing the mass air flow sensor and the air filter it became less frequent, and after changing the spark plugs (the old ones were absolutely atrocious looking), its a rare issue now, but still annoying when it happens.

Remove coil packs, sand the contact pads on each coil pack and on engine's valve cover as well, install back and torque the bolt as prescribed. This is not just a bolt that holds it in place, this is the ground contact for high-voltage circuit of the coil pack. Keep it clean and tight at all times. Loose ground contact causes misfires and premature coil pack's death.

Also avoid using non-Volvo spark plugs, our turbo engines dislikes so many of them. Rumors are Bosch FR7DPP+ is what goes into blue box, but is really worth "saving" $20 on spark plugs every 100k miles or so?

I hope it's not that, but i'll likely take it to a mechanic to check it out. (Those tools are expensive!)

Chinese DiCE is like $80.

Old Volvo with no DiCE will rob you.

[hoonk]

Can be a bad fuel pump.

Or since it is a 2006, the fuel pressure sensor might be going bad, just not bad enough to set a code.

Agree on Vida diagnostics FIRST, before replacing random $$ parts.

I always use Volvo Brand Spark plugs, and have cured many cars by simply replacing the aftermarket plugs that would missfire.

[Astro14]

My Volvo DICE unit cost me $100. Then, to make it easier to host, I bought a Windows 7 laptop on eBay for $150. It’s actually a nice machine and works well.

So, I’m into the diagnostic tool for $250.

Guessing at parts has already cost you more than that, so, wouldn’t you say that the VIDA/DICE is cheap, not expensive?

I would.

[vtl]

I got one of the first clones for $300+ back in 2010 (full featured, like illegal production on a night shift?). VIDA runs in a VM on whatever laptop I have in hands.

Paid itself a thousand times. It is very unpleasant situation when the engine starts to stall up north in Canadian tundra, 400 miles away from the nearest town, and you have no DiCE to read the codes. Turned out to be a dying DEM who knocked out BCM that ruined communication between ECM, TCM and CEM, due to one single 1/32" corroded resistor inside the DEM. DiCE/VIDA won't tell you this was that resistor, but at least you'll know what fuse to pull.

You see the resistor, right? =)