Volvo C70 2004 intermittent lagging/unresponsive.

[zpsny91]

These cars are too complex to diagnose by symptom, especially when they are spurious.

You have pretty much covered the ignition troubleshooting with coils and plugs ( yeah ME7) so start with getting fuel pressure monitored at the rail. You can sacrifice a tire pressure gauge to read this. If the pressure is marginal, the suspects are

Fuel pump relay
Fuel pump
Fuel filter

In that order.

Rented out a fuel pressure test kit. I'm assuming the gauge is broken, no readings. Will have to try again with another guage. I'm a little skeptical though, as a lot of the problems I relate to fuel pump aren't happening, like stalling/dieing at stops or difficulty starting.

[zpsny91]

These cars are too complex to diagnose by symptom, especially when they are spurious.

You have pretty much covered the ignition troubleshooting with coils and plugs ( yeah ME7) so start with getting fuel pressure monitored at the rail. You can sacrifice a tire pressure gauge to read this. If the pressure is marginal, the suspects are

Fuel pump relay
Fuel pump
Fuel filter

In that order.

I clearly do not know how to use this gauge. I am getting no reading when I hook it up and start the car. The car is running so I should definitely be getting something. I'm sure I'm using the right adapter.

[MadeInJapan]

Finally read your post after our PM's back and forth. Funny but I also thought about the throttlebody cleaning. These cars need to be done every 70 - 80,000 miles or so. Did you try taking it off and cleaning it? If so did that make a difference?

[abscate]

Can one of the experts chime in on when the c70 series switched from MM to Denso orvBosch throttle body?

I thought it was MY 2002