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05 lgt power cut?


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I have a 05 lgt 5 mt just had a new trans and front diff put in with all new axles but before all of that I noticed that in low rpm until about 3k there’s a power cut like I have a misfire or something and can’t figure out what is going on. I’ve put in new coils and plugs and it didn’t faze it so my next thing is maybe one of my cats are shot. Kind of hard to tell from the video but it lags and when the power kicks In the car jolts like crazy but when I get above 3,000 rpm everything is fine and I can hit full boost. The car is all stock except for a gfb bov. Any thoughts? I’d rather figure out what it is and fix it myself like anything else than have a shop look at it and charge me for it. Couldn’t figure out how to post a video on here so I put it on YouTube. This is the link to it. https://youtu.be/Y8sBfeWQpNg

 

 

 

 

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FWIW, every time the downpipe is removed the turbo should always be checked to shaft play.

 

You need to have most any auto parts store read the CEL for free and tell you what code it is, then tell us, before you buy anything.

Edited by Max Capacity

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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Noobie question while on the subject of turbo shaft play.....can you check the inlet side? As in while replacing the inlet or is it the exhaust side that is concerning? If so why just the exhaust side?

 

Not trying to jack from the OP....figure we can all learn as we go.

 

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Noobie question while on the subject of turbo shaft play.....can you check the inlet side? As in while replacing the inlet or is it the exhaust side that is concerning? If so why just the exhaust side?

 

Not trying to jack from the OP....figure we can all learn as we go.

 

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They are connected, if one side moving/has play, the other side will too. The DP seems to be off more then the intake side, that's why we always refer to the DP when recommending checking for shaft play.

 

Check up/down, side to side, in/out or front to back. no movement is preferred, any thing you can feel...start looking for a replacement. These things spin pretty fast.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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So In part of shaft play in the turbo I haven’t had the down pipe or the intake off to check but plan to soon. In part of the cel it’s p0420 I believe but it’s for my evap canister that’s been on it since I got the car. I have a new turbo up pipe and down pipe because I planned on upgrading anyways but I just got the car back from the transmission shop and it started before my trans went out.

 

 

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Pretty sure P0420 is your rear O2 sensor either needing a replacement, car running too rich/lean, or failing catalytic converter. If you have no way of determining air fuel ratios while driving, inspect all the intake vacuum and boost lines for leaks. These will cause whack AFRs, smoke test preferred.

 

If no leaks, test the catalytic converter with an infrared thermometer. The exit side should be much hotter coming out. But a failing O2 sensor can also cause P0420.

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Pretty sure P0420 is your rear O2 sensor either needing a replacement, car running too rich/lean, or failing catalytic converter. If you have no way of determining air fuel ratios while driving, inspect all the intake vacuum and boost lines for leaks. These will cause whack AFRs, smoke test preferred.

 

If no leaks, test the catalytic converter with an infrared thermometer. The exit side should be much hotter coming out. But a failing O2 sensor can also cause P0420.

 

 

 

Okay I have a an ir thermometer I can check that today and I can check my turbo as well but I have p0457 which is the evap. The p0420 is the 02. I’m not sure on how to do do a smoke test. I’ve seen videos on YouTube on how to do it but I’m not sure how to build the coupler for my car since I can’t take the intake box off without disconnecting the wiring to the box for my car to start. I’ll start with shaft play and the cat temps and do an update later today.

 

 

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Sounds like you have the infamous "studder". This is a very common issue, most people have fixed by replacing the fuel pressure regulator and extending the fuel hose, and some have fixed it with a retune.

 

Here's a good read - https://legacygt.com/forums/showthread.php/stutter-studder-hesitation-etc-198070.html?t=198070&highlight=studder

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Is this the only code your showing? Have you tried to clear the codes to see if it'll comeback?

 

 

So In part of shaft play in the turbo I haven’t had the down pipe or the intake off to check but plan to soon. In part of the cel it’s p0420 I believe but it’s for my evap canister that’s been on it since I got the car. I have a new turbo up pipe and down pipe because I planned on upgrading anyways but I just got the car back from the transmission shop and it started before my trans went out.

 

 

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