Bad Jerking, Studdering, Lack of Power, Shaking!!! HELP!!

[TN4Runner07]

I apologize but my old user name and email address were deleted so I had to start a new one!

*1999 4Runner SR5, V6, 200,000 miles*

Last week while driving home, I noticed a jerking at higher speeds. It was almost as if the car would not accelerate. Very weird. It happened at approx 50 mph around, 18-2000 RPM's. Although it never happened below that speed, it seemed as if something "clicked" to make it change over. The next day, it started just fine. No trouble until the engine became warm and I began to accelerate. Same symptoms. Shaking, lack of acceleration/to no acceleration, lots of jerking while trying to accelerate (putting pedal to the floor!!!), rough idle and feels like it wants to move forward while sitting at a stoplight. I noticed that the exhaust was very loud as well pulling into the neighborhood. No smoke, no burning smells, no overheating. Oil and coolant are at perfect levels. None of these symptoms began until the initial jerking occurred. IE nothing happened until the engine was warm and I started to accelerate! Very intermittent. Then it began and didn't stop until it either sat over night or cooled down. Again, no change in engine temp/oil pressure, etc. Changes/shifts gears great with no hesitation or "hard shifts". The next day I checked the codes and TPS came up along with multiple misfires in different cyc. A mechanic friend suggested that I just replace the TPS. The misfires were not actively coming up as one of the codes, the reader had said that they were "pending". I replaced the TPS sensor and it didn't help at all. I even put some seafoam in to see if it was possible a clogged fuel injector. No improvement. Of note, all new NGK plugs and wires were installed last year as well as a new MAF. I have replaced the TPS sensor, checked the spark plugs, cleaned the MAF, cleaned the throttle body and added just a bit of oil due to it begin slightly low. I apologize if a similar thread like this has been started, but I thought some of these symptoms didn't match others.

Any experiences with this? Suggestions? Thoughts? Any help would be very much appericated! Thanks!

 

[Grenvilleter]

As a matter of course, I would re-visit a close examination of wires, plugs and coil packs. Also fuel rail pressure and fuel filter.

 

[1985taylor1925]

I apologize but my old user name and email address were deleted so I had to start a new one!

*1999 4Runner SR5, V6, 200,000 miles*

Last week while driving home, I noticed a jerking at higher speeds. It was almost as if the car would not accelerate. Very weird. It happened at approx 50 mph around, 18-2000 RPM's. Although it never happened below that speed, it seemed as if something "clicked" to make it change over. The next day, it started just fine. No trouble until the engine became warm and I began to accelerate. Same symptoms. Shaking, lack of acceleration/to no acceleration, lots of jerking while trying to accelerate (putting pedal to the floor!!!), rough idle and feels like it wants to move forward while sitting at a stoplight. I noticed that the exhaust was very loud as well pulling into the neighborhood. No smoke, no burning smells, no overheating. Oil and coolant are at perfect levels. None of these symptoms began until the initial jerking occurred. IE nothing happened until the engine was warm and I started to accelerate! Very intermittent. Then it began and didn't stop until it either sat over night or cooled down. Again, no change in engine temp/oil pressure, etc. Changes/shifts gears great with no hesitation or "hard shifts". The next day I checked the codes and TPS came up along with multiple misfires in different cyc. A mechanic friend suggested that I just replace the TPS. The misfires were not actively coming up as one of the codes, the reader had said that they were "pending". I replaced the TPS sensor and it didn't help at all. I even put some seafoam in to see if it was possible a clogged fuel injector. No improvement. Of note, all new NGK plugs and wires were installed last year as well as a new MAF. I have replaced the TPS sensor, checked the spark plugs, cleaned the MAF, cleaned the throttle body and added just a bit of oil due to it begin slightly low. I apologize if a similar thread like this has been started, but I thought some of these symptoms didn't match others.

Any experiences with this? Suggestions? Thoughts? Any help would be very much appericated! Thanks!

Any change in the codes after replacing TPS? Im no expert when it comes to diagnosing engine issues, but I had very similar symptoms about 4 years ago, and my issue turned out to be an injector, #3 in my case. But I think I had the specific code for it. I remember that the stuttering/jerking/rough running occurred between certain rpms. I replaced the injector and the problem was solved. Im sure someone with more expertise will chime in soon

 

[k9doog]

Knock sensors, in my case the engine light was on with a specific code, but similar symptoms, the car couldn't go above 3000 RPM and I was able to ear the knocking from the engine.

 

[TN4Runner07]

Ok. That's the road I was going down. I think that it might be one of the injectors. Just thought that it was weird that it happened all of a sudden as opposed to a gradual decrease. I am going to disconnect the battery to hopefully clear any codes and start new then swing by an auto zone on the way home.

 

[RunnerPDX]

Here's the course I would take -- air, spark...then fuel. So checking MAF, possible vacuum issues, TB issues (although TPS is corrected)...if those are clear, go right to plugs, wires and coils. If those check out ok, onto injectors and fuel delivery.

Knock sensors can retard firing for sure, but those almost always throw a code.

 

[TN4Runner07]

Great suggestions. Thanks for the help! I hope to have some codes by this afternoon. All of these make sense. Thanks for the patience as I try to learn more!

 

[TN4Runner07]

Also, I pulled the spark plug on the front right and noticed that there was a very small amount of white powder on the outside of the wire only. Overheating maybe? Again, no temperature change on the gauge at least!!

 

[1985taylor1925]

Ok. That's the road I was going down. I think that it might be one of the injectors. Just thought that it was weird that it happened all of a sudden as opposed to a gradual decrease. I am going to disconnect the battery to hopefully clear any codes and start new then swing by an auto zone on the way home.

Mine went suddenly as well. How that works, I don't know. But it's certainly possible

 

[TN4Runner07]

So I got back horrible news today. I bite the bullet and took it to the mechanic down the road. We have used him before and he stated that the compression in Cylinder #1 was 64 PSI and suggested a engine rebuild. I plan on taking it to another mechanic to see what his thoughts were. My question is do the symptoms describe match the diagnosis?

 

[cashmoney]

I'd do a compression check yourself to verify. Dead cylinders don't magically run ok until they get warm.

 

[Sotovo]

I apologize but my old user name and email address were deleted so I had to start a new one!

*1999 4Runner SR5, V6, 200,000 miles*

Last week while driving home, I noticed a jerking at higher speeds. It was almost as if the car would not accelerate. Very weird. It happened at approx 50 mph around, 18-2000 RPM's. Although it never happened below that speed, it seemed as if something "clicked" to make it change over. The next day, it started just fine. No trouble until the engine became warm and I began to accelerate. Same symptoms. Shaking, lack of acceleration/to no acceleration, lots of jerking while trying to accelerate (putting pedal to the floor!!!), rough idle and feels like it wants to move forward while sitting at a stoplight. I noticed that the exhaust was very loud as well pulling into the neighborhood. No smoke, no burning smells, no overheating. Oil and coolant are at perfect levels. None of these symptoms began until the initial jerking occurred. IE nothing happened until the engine was warm and I started to accelerate! Very intermittent. Then it began and didn't stop until it either sat over night or cooled down. Again, no change in engine temp/oil pressure, etc. Changes/shifts gears great with no hesitation or "hard shifts". The next day I checked the codes and TPS came up along with multiple misfires in different cyc. A mechanic friend suggested that I just replace the TPS. The misfires were not actively coming up as one of the codes, the reader had said that they were "pending". I replaced the TPS sensor and it didn't help at all. I even put some seafoam in to see if it was possible a clogged fuel injector. No improvement. Of note, all new NGK plugs and wires were installed last year as well as a new MAF. I have replaced the TPS sensor, checked the spark plugs, cleaned the MAF, cleaned the throttle body and added just a bit of oil due to it begin slightly low. I apologize if a similar thread like this has been started, but I thought some of these symptoms didn't match others.

Any experiences with this? Suggestions? Thoughts? Any help would be very much appericated! Thanks!

It seems like all your major obvious stuff is fine, IE your new spark plugs and wires, new MAF, etc. it could possibly be injectors..I know you cleaned w/ seafoam, and although seafoam is amazing, In my experiences by the time it gets to the injector, it's not doing the job it should be doing, I agree with what's posted above, check your compression and look into your injectors.

 

[azcat90]

64 psi

So I got back horrible news today. I bite the bullet and took it to the mechanic down the road. We have used him before and he stated that the compression in Cylinder #1 was 64 PSI and suggested a engine rebuild. I plan on taking it to another mechanic to see what his thoughts were. My question is do the symptoms describe match the diagnosis?

What did he say was the cause of the low compression?

 

[gamefreakgc]

Compression doesn't just one day disappear like what you described. I don't think your mechanic fully understands what is going on.

Do you know the exact check engine light codes that it is showing?

 

[TN4Runner07]

So when I asked him he said "there's no telling what would cause the low compression... Burnt value probably...". I just think it's odd that I can start it up, drive 15 miles or so with no symptoms. If it was a compression issue I think it would be all the time not intermittent???

 

[LittleCaesar]

If he performed a compression test, ask him to do a leak down test. Such would be able to more closely pinpoint where the failure occurred.

A burnt valve is a possibility, but rarely have heard of any member having one.

 

[TN4Runner07]

So it was the #3 fuel injector! Took it to a mechanic who wasn't looking to replace my entire engine! If you live near Nashville/Nolensville area do not take your vehicle to Nolensville Auto Care! Thanks for the help everyone!