Sable '04 DOHC unable to accelerate, runs rough, stumbles
kantakuri
06-20-2014, 10:39 AM
Car is Mercury Sable, 2004, 24 Valve, DOHC, 110K miles.
Recent to event, things done: Oil change, new spark plugs, checked ignition coils, cleaned injectors, new fuel filter, new PCV valve and good PCV-elbow tube, cleaned EGR valve - needle moves with vacuum applied and port is not plugged, cleaned TB, IAC and MAF.
Prior performance: car was running okay but often does not respond sharply to acceleration. It performed within 18 - 22 mpg. About two weeks before event, car would not start at first crank when cold, but after it warms up or during the day, it usually starts at first crank - battery determined not the reason. Also, some rattling sound from the heatshield/exhaust area by the engine wall.
The event:
While driving car suddenly began to dramatically lose power and would not accelerate as I give it more gas. Within about 3 minutes, it would not go beyond 10 - 20 mph, jerks and stumbles as if trying to accelerate but unable to, runs rough, and NO check engine light. To go up a slight incline on the road was like crawling at snail speed. While in Park or Neutral, it idles somewhat more stable than in Drive, but still runs rough and the rpm flunctuates around 800rpm. Checked for OBD2 codes and pulled P0442 as yellow.
After event, the following services were done but not exactly in order:
Checked spark plugs-ok, PVC valve and tube-ok, EGR valve and port-ok, cleaned MAF, checked TB and IAC-ok, replaced TPS, swapped out the EGR regulator solenoid and the fuel pressure regulator with used ones, the checked for vauum leaks-none found, rattling heatshield removed (was held in place by plastic). After these services, the problem still remains - rough idle, stumbling on acceleration and not able to rev up (and hold) above about 2500rpm before it stumbles down in rpm to as low as 200rpm sometime and may even cutoff. Still no CEL code. Car now starts usually at first crank, revs to about 1500rpm for about 20 - 50 secs, then goes down to about 800 rpm and flunctuates. Still rattling sound from the exhaust area.
Please your advice will be appreciated.
Recent to event, things done: Oil change, new spark plugs, checked ignition coils, cleaned injectors, new fuel filter, new PCV valve and good PCV-elbow tube, cleaned EGR valve - needle moves with vacuum applied and port is not plugged, cleaned TB, IAC and MAF.
Prior performance: car was running okay but often does not respond sharply to acceleration. It performed within 18 - 22 mpg. About two weeks before event, car would not start at first crank when cold, but after it warms up or during the day, it usually starts at first crank - battery determined not the reason. Also, some rattling sound from the heatshield/exhaust area by the engine wall.
The event:
While driving car suddenly began to dramatically lose power and would not accelerate as I give it more gas. Within about 3 minutes, it would not go beyond 10 - 20 mph, jerks and stumbles as if trying to accelerate but unable to, runs rough, and NO check engine light. To go up a slight incline on the road was like crawling at snail speed. While in Park or Neutral, it idles somewhat more stable than in Drive, but still runs rough and the rpm flunctuates around 800rpm. Checked for OBD2 codes and pulled P0442 as yellow.
After event, the following services were done but not exactly in order:
Checked spark plugs-ok, PVC valve and tube-ok, EGR valve and port-ok, cleaned MAF, checked TB and IAC-ok, replaced TPS, swapped out the EGR regulator solenoid and the fuel pressure regulator with used ones, the checked for vauum leaks-none found, rattling heatshield removed (was held in place by plastic). After these services, the problem still remains - rough idle, stumbling on acceleration and not able to rev up (and hold) above about 2500rpm before it stumbles down in rpm to as low as 200rpm sometime and may even cutoff. Still no CEL code. Car now starts usually at first crank, revs to about 1500rpm for about 20 - 50 secs, then goes down to about 800 rpm and flunctuates. Still rattling sound from the exhaust area.
Please your advice will be appreciated.
kantakuri
06-20-2014, 10:56 PM
Some additional info:
Days before the event, I noticed that when I give it gas (open throttle the engine compartment), the plastic-top of the manifold (UIM) rises/flexes significantly. After the event, the manifold rise/flexing not as much, although the engine is now unable to accelerate beyond 2500rpm and cannot maintain the rpm.
Days before the event, I noticed that when I give it gas (open throttle the engine compartment), the plastic-top of the manifold (UIM) rises/flexes significantly. After the event, the manifold rise/flexing not as much, although the engine is now unable to accelerate beyond 2500rpm and cannot maintain the rpm.
tempfixit
06-22-2014, 06:08 PM
Some additional info:
Days before the event, I noticed that when I give it gas (open throttle the engine compartment), the plastic-top of the manifold (UIM) rises/flexes significantly. After the event, the manifold rise/flexing not as much, although the engine is now unable to accelerate beyond 2500rpm and cannot maintain the rpm.
Have you checked for a plugged exhaust ??? Try removing a oxygen sensor and see if conditions change. You could also use a vacuum gauge to check also. I will find the link and post it for you.
Solving Automotive Performance Issues
Page 9 of 10
Using a Vacuum Gauge to Check Engine Performance
This is defiantly old school but as I’ve stated over and over in this article modern engines function in the same way they always have. Your engine is an air compressor. When it’s working correctly, it’s smooth and wonderful. If it’s not working correctly it can cause performance issues. A vacuum gauge is an inexpensive tool that can tell you quite a bit about how your engine is performing. If you hook a vacuum gauge up to an intake vacuum source, it can tell you a lot about your engine’s health. On a good running engine you should see engine vacuum between 17-21inhg at idle. The needle should hold steady and not shake about. If it’s low or shakes, then you have a performance issue somewhere. I don’t want to get into all the specifics of what problems are indicated by the vacuum readings you get, but I do want to make you aware of this tool and it’s capabilities. Even if you just hooked up the gauge and observed the reading you would have a pretty good idea of how your engine is performing. At some point I may do an article just on using a vacuum gauge. For now you can use this next test to see if you have and exhaust restriction. It’s a pretty cool test, I think you’ll like it.
http://ericthecarguy.com/images/faq_buttons/Perfromance/Vacuum_Tester.jpg
Using a Vacuum Gauge to Find Exhaust Restrictions
As long as we're on the topic of engine mechanicals, let’s talk about the effects of a restricted exhaust. Imagine being able to breathe in but not out. It wouldn't be long before you pass out cold. The same thing can happen to your engine. If you have a restricted exhaust due to a catalytic converter failure, damage to the pipes themselves, or a restricted muffler, your engine will be sluggish and underpowered. Surprisingly, testing for this isn't that difficult. All you need is a trusty vacuum gauge. To use a vacuum gauge to find an exhaust restriction, you first need to find a place on your intake where you can hook the gauge up. You're looking for an intake vacuum source. This would be a source that has high vacuum at idle. Look for a line connecting somewhere after the throttle body. Pull it off while the engine is running. If you feel vacuum there, that's where you want to hook up. On a good-running engine, intake vacuum should be between 17 to 21 INHG. (That's inches of mercury for those of you who are curious.) Vacuum is also measured in Bar, but for this article we're going to use INHG.
The needle on the gauges should also hold steady and not bounce around. If it does, this might indicate a mechanical issue with the engine. Also, intake vacuum is highest at idle and drops off to zero the closer you get to wide open throttle (WOT). With the engine running, take your first reading. Raise the RPM to about 2000 or 2500 and watch the gauge. If you have an exhaust restriction, you'll begin to notice that vacuum will slowly drop off over time, and it might be harder to maintain the RPM. If the vacuum remains the same, then you don't have a restriction and you can move on to other tests. Here's a video showing the test in action.
http://www.youtube.com/watch?v=d-jp1IIJVVk
Days before the event, I noticed that when I give it gas (open throttle the engine compartment), the plastic-top of the manifold (UIM) rises/flexes significantly. After the event, the manifold rise/flexing not as much, although the engine is now unable to accelerate beyond 2500rpm and cannot maintain the rpm.
Have you checked for a plugged exhaust ??? Try removing a oxygen sensor and see if conditions change. You could also use a vacuum gauge to check also. I will find the link and post it for you.
Solving Automotive Performance Issues
Page 9 of 10
Using a Vacuum Gauge to Check Engine Performance
This is defiantly old school but as I’ve stated over and over in this article modern engines function in the same way they always have. Your engine is an air compressor. When it’s working correctly, it’s smooth and wonderful. If it’s not working correctly it can cause performance issues. A vacuum gauge is an inexpensive tool that can tell you quite a bit about how your engine is performing. If you hook a vacuum gauge up to an intake vacuum source, it can tell you a lot about your engine’s health. On a good running engine you should see engine vacuum between 17-21inhg at idle. The needle should hold steady and not shake about. If it’s low or shakes, then you have a performance issue somewhere. I don’t want to get into all the specifics of what problems are indicated by the vacuum readings you get, but I do want to make you aware of this tool and it’s capabilities. Even if you just hooked up the gauge and observed the reading you would have a pretty good idea of how your engine is performing. At some point I may do an article just on using a vacuum gauge. For now you can use this next test to see if you have and exhaust restriction. It’s a pretty cool test, I think you’ll like it.
http://ericthecarguy.com/images/faq_buttons/Perfromance/Vacuum_Tester.jpg
Using a Vacuum Gauge to Find Exhaust Restrictions
As long as we're on the topic of engine mechanicals, let’s talk about the effects of a restricted exhaust. Imagine being able to breathe in but not out. It wouldn't be long before you pass out cold. The same thing can happen to your engine. If you have a restricted exhaust due to a catalytic converter failure, damage to the pipes themselves, or a restricted muffler, your engine will be sluggish and underpowered. Surprisingly, testing for this isn't that difficult. All you need is a trusty vacuum gauge. To use a vacuum gauge to find an exhaust restriction, you first need to find a place on your intake where you can hook the gauge up. You're looking for an intake vacuum source. This would be a source that has high vacuum at idle. Look for a line connecting somewhere after the throttle body. Pull it off while the engine is running. If you feel vacuum there, that's where you want to hook up. On a good-running engine, intake vacuum should be between 17 to 21 INHG. (That's inches of mercury for those of you who are curious.) Vacuum is also measured in Bar, but for this article we're going to use INHG.
The needle on the gauges should also hold steady and not bounce around. If it does, this might indicate a mechanical issue with the engine. Also, intake vacuum is highest at idle and drops off to zero the closer you get to wide open throttle (WOT). With the engine running, take your first reading. Raise the RPM to about 2000 or 2500 and watch the gauge. If you have an exhaust restriction, you'll begin to notice that vacuum will slowly drop off over time, and it might be harder to maintain the RPM. If the vacuum remains the same, then you don't have a restriction and you can move on to other tests. Here's a video showing the test in action.
http://www.youtube.com/watch?v=d-jp1IIJVVk
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