All,

I have a 2001 V6 with 42K on it and I just recently noticed that the engine appears to shudder intermittently while I'm driving. The engine idles fine and the problem is most noticable while I'm at highway speeds: 65-70mph. The problem does come and go, and while it's happening if I back off the gas the shuddering will actually get worse. However, the problem usually goes away within a mile or two.

Any ideas as to what might be causing this? Seems like a emission control or other sensor issue to me, like maybe my O2 sensor is on its way out. Any input on this would be welcome! Also, if anyone knows how to read codes without a computer that would be great! I prefer to do my own maintenance and my manual has nothing on the topic.

Thanks,
Matt

 

Is the transmission auto or manual? If auto,its most likely a shudder problem there.More info,please!

 

Sorry about that! I probably should have included tranny type. It is an automatic, and I suppose the issue could be there. But from what it feels like to me, it's more of a bog/shudder in the motor, especially considering that it's intermittent + it gets worse (while it's happening) when I back off the gas. Also, while experiencing the issue, if I step on the gas, the engine seems to hesitate as well. Anything's possible, though.

Matt

 

Ok,lets talk about the basics here.When was the last transmission service? Includes,pan,filter,and torque convertor drain. If you think its not tranny related,when was the fuel filter last changed? Have you ever cleaned the throttle body?

 

All good questions!!!

But seeing that I'm the second owner (38K on it when purchased), I don't have a great deal of insight into previously done maintenance. From what I can tell, though, the original owner was pretty good about keeping up with oil changes and other "run of the mill" type maintenance. However, I'm guessing the transmission has probably not been serviced as of yet. I'll have to take a look at the fuel filter (guessing it's mounted on the frame rail) but I doubt that's been changed either.

Matt

 

Oh, and how do I clean the throttle body: injector cleaner in the tank or some sort of spray directly into the unit?

Matt

 

To clean the throttle body go to a parts store and buy a can of THROTTLE BODY CLEANER,ONLY! Do not use carb cleaner!
Remove the the 90* elbow from the TB.Spray the cleaner inside the TB at the same time opening the butterfly and spraying the back side of it.Get a soft bristle tooth brush and scrub the inside of the TB,and the front and back side of the butterfly.Rinse it all down again and put the elbow back on.When you start it up there will probably be a little hesitation and smoke;once that is over enjoy the benefits of better throttle response and more power!
About the fuel filter,go to the "Technical Articles" on the left side of the forum board and there is a "how-to" on changing the fuel filter.Also,there are other links at the end of the tech.articles.Click onto them and you will find a "how-to" on flushing/draining your transmission and torque convertor.Good luck and keep us posted!

 

Well, it might be too early to tell, but I think I might have found & fixed the issue that's been causing my shudder problem. I went through the emission system part by part and reseated and, in some cases, cleaned the connectors on all the major sensors involved. I didn't really see any major corrosion on any of them, but since going through the system everything seems to be running smoothly again. I'm still going to clean the throttle body as well as change the fuel filter, so thanks again for the guidance there! Again, I hope I'm not calling it good too early but all seems OK now.

Thanks again,
Matt

 

I wonder if your situation is related to mine....My truck's 4.2 shudders whenever I make the first or second stop after being on the highway for a couple hours. I have to hold the brake and rev the engine to get it to stop. Hmmmm.

 

Hey MyFordTruck98,

I can't say for sure that this advice will help with the problem your experiencing, but I wanted to share what I believe is a fairly "MAJOR FINDING" when it comes to diagnosing & fixing rough running engines, to include both V6s & V8s.

As I mentioned in my previous posts, I had gone through most of my emission system sensors to clean them up and hopefully get my engine to run better & smoother. However, having bought my truck used (38K on it), I didn't really have a good feel for exacty what a smooth running 4.2 felt like.

Well, that all changed the other day when I went out to start my truck and it didn't start easily and ran "very rough" after it did start. After that, I started checking under the hood for anything that might have contributed to the hard start and rough idle, figuring that I would again look at the emission system. I though about it and remembered that my engine seemed to knock more than it should at times and after reading about the job of the KNOCK SENSOR (mounted on right side of block {as you'er sitting in the driver's seat} and adjusts ignition timing based on engine vibration), I started there.

To make a long story short, when I took apart the sensor's connector (between sensor and main harness), it was pretty badly corroded. In fact, it was the only emission system connector that had real "visible" corrosion on it. I cleaned it, put it back together, started the truck; and low and behold, the engine ran as smooth as glass both at idle and at speed. The difference was literally like night & day. In fact, I'd bet "dollars to doughnuts" that the excess vibration was the main reason the truck was probably sold in the first place, as there was no code, meaning it would have been difficult to diagnose.

Anyway, it's probably worth a look-see for you and/or anyone else who might have a rough running motor!!!

Good luck,
Matt