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Discussion Starter · #1 ·
Here is what happened...I had a CEL for the front O2 sensor on my 98 V70R. While I was investigating how to reach the sensor to replace it I cracked the PCV hose near the turbo end. So I had to order that, I watched a few videos on how to do it and seemed pretty straight forward except for it being a lot of work. I figured while I was in there I would clean up stuff, replaced some old vacuum lines that I hadn't already done in the past. I also replaced my cbv with a forge unit I had sitting around that I never had installed because its a pita. So after all parts came in I put everything back together, everything went back together normal, no leftover parts or bolts:) But now when I start it up, it jumps to about 4k rpm for a couple seconds then drops down until it shuts off, takes about 3-4 seconds. It does the same thing every time, I don't even step on the gas pedal, it just revs all by itself, and starts right up ever time. As far as I can tell all vacuum lines are back where they are supposed to be and everything plugged back in. I am going to borrow a neighbors car to do a comparison. In the meantime...any suggestions on what it could be, what would make it rev up and then die?
 

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Very similar problem happened to me when I put the intake manifold back onto the block after doing my PCV system. My problem was that the retaining clip was put on incorrectly and was pinching the line. I had to pull the intake off again and reinstall the clip the proper way, I think many people make this mistake. No judgement!
 

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Very similar problem happened to me when I put the intake manifold back onto the block after doing my PCV system. My problem was that the retaining clip was put on incorrectly and was pinching the line. I had to pull the intake off again and reinstall the clip the proper way, I think many people make this mistake. No judgement!
heh....I just didn't reinstall the clip at all, the hose holds itself in place just fine. Not on purpose though, I just forgot about it on reinstall and said screw it, probably fine. Many miles and years later, no issues.


To OP, check your charge pipes (the air pipes from turbo to intercooler then intercooler to throttle body). That's how the car acts if one of the connections has come off.
 

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Discussion Starter · #5 ·
What retaining clip are you talking about? I did find the spring on the throttle body was loose, not sure if it is broken or just came un sprung and maybe I can rewind it? Not sure what it does but do you think it can be my issue and do we know how to fix it?
Very similar problem happened to me when I put the intake manifold back onto the block after doing my PCV system. My problem was that the retaining clip was put on incorrectly and was pinching the line. I had to pull the intake off again and reinstall the clip the proper way, I think many people make this mistake. No judgement!
 

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The clip is on the far right (when standing in front of the car and looking at the engine) intake manifold bolt, it's a small bracket that just holds the PCV lines away from the block a bit, doubt it's your issue though.

Did you check all your intercooler piping? Turbo to intercooler, intercooler to throttle body. One of those being off a bit can do what you're describing.
 

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Discussion Starter · #7 ·
I found the spring on the throttle body linkage to be sprung, I guess the bracket that holds in place was bent and let the spring loose its tension. I guess that happened when I took the intake manifold off and bent over out of the way while doing the PCV piping. Was able to put it back in place with tension, just waiting now for the TB gasket to come in tomorrow so I can put it all back together and test it.
 
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