1999 XC70 Bucks, Surges, Runs Rough

[Donzilla]

Well, I'm back at it again. Bought the car with 199 on it, it has 202 on it now.

Previous symptoms led to ordering a new OE replacement fuel pump and installing it --- many thanks to all on this forum. Also changed the fuel filter and black gas and goo ran out of it. (Maybe I shouldn't be filling up at Safeway??!) This cured the starting issues. It was throwing P0137 so I replaced the (rear) oxygen sensor.

However, Sunday --- which was a BEAUTIFUL day in the PNW, I might add --- we drive about 40 miles. The first half was fine, but the second half we were limping along, unable to get the car to rev above 2100 or so RPM, surging and bucking if we try to rev it too high. We got codes 0300, 0304, 1171, 1174, 1037 at different times...

When we finally got to our destination I cleaned the MAF with MAF spray, refreshed the K&N air filter, and put new spark plugs in. The spark plugs were incredibly fouled, worse than I've ever seen!

Now it starts and runs, and when it's first being driven after sitting it accelerates ok and goes into the higher RPMs (though it never gets above 4K...even in P). BUT, after driving it for a bit it gets worse and worse... The RPM it can handle gets lower and lower. If you are at speed and push the gas pedal down where if would kickdown or rev higher, the car stops accelerating altogether. So it's impossible to really drive anywhere. Hills and highways don't work, unless you can find an incredibly long, downhill on-ramp to get up to speed on!

With the car idling, unplugging the MAF kills it instantly. It will start and idle (a bit more roughly but pretty stable actually) with the MAF unplugged. I haven't taken it for a test drive with the MAF unplugged yet.

Thought? Thanks!
Don

[FCPEURO]

Well, it sounds like you have a bad vacuum leak. Have you looked for any loose hoses?

[BEJinFbk]

It sounds like you have a '99 with a doomed ETM.
( They're ALL doomed...) Time for XeMODex!
For more on the issue, here's the link to click:

https://www.matthewsvolvosite.com/forums ... m.php?f=12

[Donzilla]

Well, it sounds like you have a bad vacuum leak. Have you looked for any loose hoses?

Yes... but not thoroughly. Also, I now realize that I need to clean the PCV system. I have the "classic" symptoms of oil blown all over the top of the engine under the spark plug cover, foul smells coming into the passenger compartment through the front vents, probable RMS leak, and faint white smoke coming out of the dipstick tube when warmed up.

Meanwhile I'll look all over for worn or cracked vacuum tubes...thanks!

[Donzilla]

It sounds like you have a '99 with a doomed ETM.
( They're ALL doomed...) Time for XeMODex!
For more on the issue, here's the link to click:

https://www.matthewsvolvosite.com/forums ... m.php?f=12

Ah, yes. I figure sooner or later I'll upgrade to the XeMODex. That's the one thing I was figuring I'd have to do to this car before I bought it. (Although the ETM was replaced at least once, albeit with the same flawed part).

Thanks!

[Donzilla]

Popped in a new MAF ($116 NAPA, with the AAA discount) and it runs great. Took two minutes to do as I had an extra set of hands to help pop off the air tube.

Car has power accelerating, winds up past 4K to 5K, etc etc. The only thing that may still be iffy is the kickdown at higher speed, I can't quite tell if that is working 100%.

Next: I'm going to do the PCV with the FCP Groton kit.

[JRL]

99 and newer won't rev past about 4k in park!
Built in rev limiter

[Donzilla]

99 and newer won't rev past about 4k in park!
Built in rev limiter

Thanks, JRL, that answers that!

Now, the car drove perfectly for three days, then same exact issues, codes 1174, 0137, 1171. *throws hands up in air*

I'm going to do the PCV thing, and check for vacuum leaks like FCPGroton suggested...any other ideas? Thanks!