Please help diagnose power loss/miss problem.
#1
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Please help diagnose power loss/miss problem.
Hey guys, just picked up a 1999 ES300 that is having a strange issue.
When you accelerate from a stop at full throttle, the car feels very sluggish moving up the RPM range, and acts as though it is missing the entire way up. If you do the same acceleration at lets say 70-80% throttle its much faster and much smoother (like the car is supposed to be). Works just fine until the car hits like 55mph, then power just cuts out.
If I'm revving the car in park or neutral its the same story. Works well at part throttle, but full throttle it misses as its revving up.
To me this seems like 100% some kind of weird electrical issue. I'm having a tough time tracking it down though.
Things I have done:
1. At one point i had an VVTi OCV code for the rear bank, so I've replaced both OCV filters, and removed tested and replaced the RH OCV valve (they were both working to spec, but the rear one had a little more play in it).
2. No codes by OBDii scanning.
3. Cleaned MAF
4. Checked intake hoses for rips (there are none)
5. TPS seems to be working well based on OBDii diagnostics.
I'd appreciate any other ideas you guys have.
When you accelerate from a stop at full throttle, the car feels very sluggish moving up the RPM range, and acts as though it is missing the entire way up. If you do the same acceleration at lets say 70-80% throttle its much faster and much smoother (like the car is supposed to be). Works just fine until the car hits like 55mph, then power just cuts out.
If I'm revving the car in park or neutral its the same story. Works well at part throttle, but full throttle it misses as its revving up.
To me this seems like 100% some kind of weird electrical issue. I'm having a tough time tracking it down though.
Things I have done:
1. At one point i had an VVTi OCV code for the rear bank, so I've replaced both OCV filters, and removed tested and replaced the RH OCV valve (they were both working to spec, but the rear one had a little more play in it).
2. No codes by OBDii scanning.
3. Cleaned MAF
4. Checked intake hoses for rips (there are none)
5. TPS seems to be working well based on OBDii diagnostics.
I'd appreciate any other ideas you guys have.
#3
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Good thought, the only thing that made me not really consider that is this.
If I accelerate at full throttle and its stumbling through the rpms, if i decrease the throttle to 80% the car actually picks up and accelerates faster. I'll probably replace it anyways since its cheap.
Could a vacuum leak cause symptoms like this? I'm under the impression that the 1999 1mz-fe vvti doesn't have EGR, so that isnt a consideration correct?
If I accelerate at full throttle and its stumbling through the rpms, if i decrease the throttle to 80% the car actually picks up and accelerates faster. I'll probably replace it anyways since its cheap.
Could a vacuum leak cause symptoms like this? I'm under the impression that the 1999 1mz-fe vvti doesn't have EGR, so that isnt a consideration correct?
#4
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Good thought, the only thing that made me not really consider that is this.
If I accelerate at full throttle and its stumbling through the rpms, if i decrease the throttle to 80% the car actually picks up and accelerates faster. I'll probably replace it anyways since its cheap.
Could a vacuum leak cause symptoms like this? I'm under the impression that the 1999 1mz-fe vvti doesn't have EGR, so that isnt a consideration correct?
If I accelerate at full throttle and its stumbling through the rpms, if i decrease the throttle to 80% the car actually picks up and accelerates faster. I'll probably replace it anyways since its cheap.
Could a vacuum leak cause symptoms like this? I'm under the impression that the 1999 1mz-fe vvti doesn't have EGR, so that isnt a consideration correct?
Last edited by PFB; 12-30-11 at 01:52 PM.
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I'll swap the fuel filter tomorrow.
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Newish development:
Was tracing all of the vacuum lines and noticed that several were just flat out cut through. The two going to the vacuum tank were folded back on themselves and ziptied and the other two were just sliced.
Could this be the source of my problems? I shall fix it tomorrow and see.
Was tracing all of the vacuum lines and noticed that several were just flat out cut through. The two going to the vacuum tank were folded back on themselves and ziptied and the other two were just sliced.
Could this be the source of my problems? I shall fix it tomorrow and see.
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#8
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https://www.clublexus.com/forums/es3...finally-d.html
Last edited by PFB; 01-01-12 at 01:50 PM.
#9
You need a scan tool that shows streaming data so that someone can ride along and see what the engine is doing while you drive. Sounds like it might be starving for fuel. I'd check fuel pressure while driving. Could be a failing fuel pump. Hard to say without more information. You don't have an EGR valve and that wouldn't cause any high speed driveability issues anyway. You might consider a clogged catalytic converter as well...
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You need a scan tool that shows streaming data so that someone can ride along and see what the engine is doing while you drive. Sounds like it might be starving for fuel. I'd check fuel pressure while driving. Could be a failing fuel pump. Hard to say without more information. You don't have an EGR valve and that wouldn't cause any high speed driveability issues anyway. You might consider a clogged catalytic converter as well...
I also noticed a sulfery smell from the exhaust when messing with the car today. I bet its the cat.
#11
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Turned out to be a combination of a crusty fuel strainer and moreso a faulty fuel pressure regulator. Only sign that the fuel pressure regulator was going was that the fuel pressure was 51-52 instead of just below 50.
Car runs like a champ now.
Car runs like a champ now.
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