Engine engine bogs down over 2500 rpm

The EVAP line goes from the right hand fender well to a vacuum port. For the 1996-1998 model year the EVAP line goes from the the throttle body to the Purge flow sensor, then onto the purge solenoid. From there it goes into the right hand fender well.

Didn't you buy a new EVAP solenoid and purge flow sensor? It's on the same vacuum line.

From the picture it looks like the larger vacuum line with the red stripe.
 
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The EVAP line goes from the right hand fender well to a vacuum port. For the 1996-1998 model year the EVAP line goes from the the throttle body to the Purge flow sensor, then onto the purge solenoid. From there it goes into the right hand fender well.

Didn't you buy a new EVAP solenoid and purge flow sensor? It's on the same vacuum line.

From the picture it looks like the larger vacuum line with the red stripe.
I replaced these 4 sensors. The bottom area circled is the IAC. The arrow to the left is the purge canister.
 

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Two of the parts circled are for the EGR system. The upper right part is the DPFE sensor. The part near the middle is the EGR vacuum solenoid.

As stated very early on in this thread that excessive EGR flow can cause loss of power. The key to this whole problem is to figure out WHAT changes when the problem occurs.

In the same way as trouble shooting an EVAP problem the way to trouble shoot a suspected EGR problem is to monitor the DPFE sensor. Looking for an increase in EGR flow when the problem occurs.

The low tech approach is to disconnect and plug the EGR vacuum line. Does this improve the issue? The limitation of this method is it won't work IF the EGR valve is stuck open. For this a manual block off gasket between the EGR valve and the TB is what the doctor ordered.
 
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Two of the parts circled are for the EGR system. The upper right part is the DPFE sensor. The part near the middle is the EGR vacuum solenoid.

As stated very early on in this thread that excessive EGR flow can cause loss of power. The key to this whole problem is to figure out WHAT changes when the problem occurs.

In the same way as trouble shooting an EVAP problem the way to trouble shoot a suspected EGR problem is to monitor the DPFE sensor. Looking for an increase in EGR flow when the problem occurs.

The low tech approach is to disconnect and plug the EGR vacuum line. Does this improve the issue? The limitation of this method is it won't work IF the EGR valve is stuck open. For this a manual block off gasket between the EGR valve and the TB is what the doctor ordered.

I blocked off the hose (as photo shows), it didn't improve the issue.
I then made a metal shim and installed between the EGR and TB, this also didn't improve the issue.

Also through all this I never got a engine code.
 

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The vacuum hoses in question control the EGR system. When disabling the EGR system and not getting any improvement, this tends to say that EGR is not your issue.

How about the EVAP system? Have you disconnected and plugged the EVAP line?

In all of this check this and check that, it still seems to me that some "basic" information is missing. To me this seems odd considering that you do have access to advanced ODB2 data. For example:
  • What do short term fuel trims bank1 and bank2 (STFT) do just before and after this problem occurs?
  • What do LTFT's do when this problem occurs?
  • How does the timing advance change as this problem occurs?

OBTW, what have you done to rule out a blocked exhaust?
 
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The vacuum hoses in question control the EGR system. When disabling the EGR system and not getting any improvement, this tends to say that EGR is not your issue.

How about the EVAP system? Have you disconnected and plugged the EVAP line?

In all of this check this and check that, it still seems to me that some "basic" information is missing. To me this seems odd considering that you do have access to advanced ODB2 data. For example:
  • What do short term fuel trims bank1 and bank2 (STFT) do just before and after this problem occurs?
  • What do LTFT's do when this problem occurs?
  • How does the timing advance change as this problem occurs?

OBTW, what have you done to rule out a blocked exhaust?

I disconnected the EVAP (black hose with red strip) from the t connector coming off of the throttle body. I plugged the t connector and the hose. No difference (it actually seemed to make it worse, meaning it appeared the condition occurred a few seconds earlier)


At Idle1st 30 Seconds of Driving (No Bog)When I'm driving and have the bog
SFTF13.96.232.8
SFTF23.95.532.8
LFTF1-3.90.8-3.1
LFTF2-3.10.8-1.6
Timing Advance11.522.526
Boost/Vacuumv21.3B11.1V4.8
Coolant199.4188.6203


Rule out blocked exhaust.
I've let it run for a little over 1 hour while idling. It never cut off.I thought maybe this ruled out exhaust?
I know the muffler is not blocked, as it has a pretty good size hole in it :) Not positive on the catalytic converter.
 
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The only way I know of to positively rule out a blocked cat is to measure the pressure before and after the cat. A basic health check can be done by removing the O2 sensor and measuring the pressure at the O2 bung hole.

Another exhaust health check is the measure the intake manifold vacuum. It will show up as low vacuum at idle. But will have a decreasing unstable vacuum under stable RPM (say 2500 RPM)

In the data dump above note the STFT. The PCM is adding fuel at a large rate. Also note that it's the same on both banks. What we don't know is if this is the problem or a symptom of the problem.

Refresh my memory. Has the fuel pressure been monitored while driving?

If this were my car I would "record" a running list of:
  • RPM's
  • MAF
  • O2 voltage bank 1 sensor 1 and bank 2 sensor 1.
  • STFT bank 1 and bank 2.
  • TPS
Drive the car until the problem occurs. This will crate fairly large data set. This is where having good Excel skills will pay off. The key is to graph the data from a common origin point so that trends over time can be seen. IE which happens first? Or is there a build up until the STFT limit is reached?

Specifically I want to know how the O2 sensors are switching just before the problem happens. In fact pay close attention to any sensor that changes right before the STFT go through the roof.
 
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I'm still bothered by the obviously unstable ECT sensor. 118.6 is why too low. This will affect HOW the PCM alters the AF mixture. As part of the same run it obviously points to a problem if part of the same run.

The only way I know of to positively rule out a blocked cat is to measure the pressure before and after the cat. A basic health check can be done by removing the O2 sensor and measuring the pressure at the O2 bung hole.

Another exhaust health check is the measure the intake manifold vacuum. It will show up as low vacuum at idle. But will have a decreasing unstable vacuum under stable RPM (say 2500 RPM)

In the data dump above note the STFT. The PCM is adding fuel at a large rate. Also note that it's the same on both banks. What we don't know is if this is the problem or a symptom of the problem.

If this were my car I would "record" a running list of:
  • RPM's
  • MAF
  • O2 voltage bank 1 sensor 1 and bank 2 sensor 1.
  • STFT bank 1 and bank 2.
  • TPS
Drive the car until the problem occurs. This will crate fairly large data set. This is where having good Excel skills will pay off. The key is to graph the data from a common origin point so that trends over time can be seen. IE which happens first? Or is there a build up until the STFT limit is reached?

Specifically I want to know how the O2 sensors are switching just before the problem happens. In fact pay close attention to any sensor that changes right before the STFT go through the roof.

I'm sorry, that was a typo the coolant was 188.6 not 118.6. I edited the post above.

I have checked the fuel pressure while running. I will try and do that again.
Before I was getting low pressure and hard to crank. I replaced the pump. I honestly can't remember if I had these bogging problems before I changed the pump.
If I were to drop the tank again is there anything I should be on the lookout for? Should I have replaced the entire pump (sending unit etc.) instead of just replacing the pump itself.
 
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The only way I know of to positively rule out a blocked cat is to measure the pressure before and after the cat. A basic health check can be done by removing the O2 sensor and measuring the pressure at the O2 bung hole.

Another exhaust health check is the measure the intake manifold vacuum. It will show up as low vacuum at idle. But will have a decreasing unstable vacuum under stable RPM (say 2500 RPM)

In the data dump above note the STFT. The PCM is adding fuel at a large rate. Also note that it's the same on both banks. What we don't know is if this is the problem or a symptom of the problem.

Refresh my memory. Has the fuel pressure been monitored why driving?

If this were my car I would "record" a running list of:
  • RPM's
  • MAF
  • O2 voltage bank 1 sensor 1 and bank 2 sensor 1.
  • STFT bank 1 and bank 2.
  • TPS
Drive the car until the problem occurs. This will crate fairly large data set. This is where having good Excel skills will pay off. The key is to graph the data from a common origin point so that trends over time can be seen. IE which happens first? Or is there a build up until the STFT limit is reached?

Specifically I want to know how the O2 sensors are switching just before the problem happens. In fact pay close attention to any sensor that changes right before the STFT go through the roof.

Okay I think I found the smoking gun today...maybe..
I put the fuel pressure gage on the fuel rail via the schrader valve today and took it for a spin.Once I got down the road some the fuel pressure dropped down to almost zero when the problem started.
I get 30psi at idle. Before I replaced the fuel pump I was getting 20psi.
I only replaced the fuel pump itself (not the sending unit etc)
Could it be the pump? Or something I didn't hook-up right? 1 thing also to keep in mind the fuel filter will not snap into the line fittings. The white connectors go on, although no fuel tool is required to remove the lines. I don't believe it is leaking here because no fuel is seen around area.

This is what I purchased Amazon product ASIN B07BFBMZCTView: https://www.amazon.com/gp/product/B07BFBMZCT/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
 
Once I got down the road some the fuel pressure dropped down to almost zero when the problem started.
Low fuel pressure fits the reported symptom.

Since this problem occurs the fuel requirements are greater there are some other things I think should be ruled out before dropping into changing yet another fuel pump. For example, what is the voltage at the trunk mounted IFS switch when the problem occurs? IF the voltage drops this means there's an electrical problem upstream of the IFS switch.

This is a 1998 model year right? This model year also has a two speed fuel pump relay with a ballast resister. If this were my car, I would be double check that the relay works on BOTH speeds. What if the relay isn't switching? Or isn't making good contacts? A problem here could easily explain WHY the fuel pressure is dropping when it is.
 
Glad to hear that. This is a good lesson in what can be done by testing and going where the evidence points. It also confirms that sometimes a new part isn't a "good" part.

Did you find any evidence of WHY the recently replaced fuel pump apparently went bad sooooooooooo quickly?

No, the pump was only a few weeks old. Everything looked fine on it. This time I replaced the entire fuel pump and not just the pump itself.