Another Rough Idle Thread

[wedge1]

I think that I have read just about every "rough idle" thread on this site and on the other site. I feel that I'd like to have a little more specific information regarding what I should do next. The car has almost 158,000 miles. The spark plugs were changed at about 97,000 miles and are not AC Delco 41-110 as they should be. Sorry, but I didn't start reading these soon enough. The plugs are Champions. The heated oxygen sensors (HO2S) have never been changed. The tachometer stays steady when the idle is rough, but I can watch the engine twitch as it misses.

I cleaned the throttle body and MAF sensor about 30,000 miles ago, and I did that again today. It didn't help the rough idle. Last Saturday, I thought that I would have a try at changing the HO2S. After spraying the sensors with WD-40, they came loose fairly easily, and I took the one on the right (passenger) side out. From underneath, I could barely touch the connector above the bell housing. Having read it in one of the threads, I took some wire and pulled the sensor up. I got it to where I could see it and get one hand onto it. Unfortunately, the connector is a two-hand connector. It was so near but so far. I gave up and pushed it back down. I put a little bit of anti-sieze on it and reinstalled it and tightened up the one on the left (driver) side. The Service Manual procedure to change the HO2S includes things like lowering the transmission and whatever else goes with that.

So what's next? Maybe I'll add a can of Sea Foam at my next fuel fillup. Maybe next would be a set of the correct (AC Delco 41-110) spark plug. From reading the other threads, I understand that it can be done by a DIYer. And after that I will need help with those HO2S. I'm afraid that I'm coming up on a smog check in a month or two. With the information that is available on this site, I'd like your help and opinions. Thanks in advance. Wedge1. (The name has nothing to do with the blue oval. A wedge is the simplest tool known to man.)

 

[gmcman]

You need to remove the Champions and install the correct AC plugs.

Correct plugs are 41-103, do not attempt to gap them. Check the gap and if they are within about .002 leave them alone. If one is way off, return it to for a replacement or check before you leave. Be sure to use dielectric grease on all the plug tips. Torque coil pack bolts to 89 inch-pounds, and plugs to 15 foot pounds or 180 inch pounds.

Use anti seize on the plug threads and coil pack bolt threads. Would be a good idea to replace the upstream O2 sensor with an AC unit if the refresh rate on the sensor is more than 1hz.

 

[The_Roadie]

41-103 for I6. I forget the one for the V8.

 

[gmcman]

41-103 for I6. I forget the one for the V8.

Whoa....I completely missed that in his profile, thanks.

 

[The_Roadie]

On Tapatalk, there is no displayed profile in the thread view. Makes me slow down with my sometimes too-quick answers.

 

[BRomanJr]

I agree with the plug swap, get the AC Delco Iridiums in there (peace of mind for me).

I have high miles also (190k) and my engine is not super smooth but replacing both front O2 sensors (Delphi) smoothed it out a lot and seemed to get me .5 MPG back.

 

[signalnc]

I'm not familiar with the 8cyl, but I'll give my input

I think he said in his post the delco's are 41-110's for the 8cyl--I'm not sure if the 8cyl is as picky as the 6 cyl, but I know I would rip those champions out and put in delco's.

O2's sensors have never been changed at 158k --I would think they are over due, at least the upstream..I'm not familiar with the v8, and how many it has or locations. The I6 has the upstream right on the side of the exhaust manifold.

I would also clean the throttle body again, and do the re-learn after you clean it.

are you getting a SES (check engine) light? if so what codes? is it an actual mis fire or is the idle not steady?

 

[wedge1]

Thanks for the quick responses. It looks like new plugs are the next job. I'm about 99% sure that the 41-110 plugs are the correct ones. I know that some people have done it themselves by going through the wheel well on the passenger side so I'll try that. If anyone has an idea on this, let me know. Yes, anti-sieze is a must.

I'm not getting the SES (MIL) light on this.

I did take the ground wire off of the battery while I cleaned the throttle body.

I'd like to hear from someone with the 5.3L V8 that changed the HO2S and how they did it. There are a total of four sensors, two in front of the cat and two behind it. Thanks again for your responses.

 

[signalnc]

on the I6, there is a throttle body relearn after cleaning it ( I think it's just turn key to on but don't start the engine, leave for 10 minutes, then start it without pressing the gas pedal). I'm not sure if the v8 has the same. All I can tell you is I had idle issues with my I6 because I did not do the relearn.

 

[wedge1]

After running into a problem while trying to change the Heated Oxygen Sensors (HO2S), I decided to try my luck with changing the spark plugs and ignition wires. I put in AC Delco 41-110 spark plugs. When I finished, we took it for a short (9 miles) drive. It ran very well. It has been a long time since it ran that smoothly.

Now for the details: It is a difficult job. It took me about 5 hours. This included the time to locate and retrieve the socket when I dropped it while working on #4. The most difficult cylinder is #2. It is right next to the strut tower. It is best gotten from above. Remove the tube between the MAF and the throttle body. Remove the MAF. Remove the top of the air filter box. Remove the air filter. Unbolt the bottom of the air filter box and tip it forward. This item doubles as the windshield washer reservoir. Now #2 is visible and accessible. To get to #4, #6, and #8, remove the passenger side front tire. These three can be accessed from the wheel well. The #4 is slightly behind the strut tower, but it is accessible. The #6 is visible, and #8 is done mostly by feel. On the driver side, they are accessible from above. The #7 was harder to get than it looked like it should be. The #1 is behind the power steering filler pipe but can be gotten. The #3 and #5 are relatively easy. So there you have it, new plugs and wires.

That leaves the question of what to do about the HO2S. As long as it runs as it did during the test drive, the answer is, "Nothing." But I'm sure that the time is coming. I'm going to have to get a smog check in a month or two. I wonder if the connectors would be accessible from the wheel well. I should have looked at this when I had the tire off. I will do that some time, but I doubt that they could be reached. Thanks for listening, and I'm always open to suggestions.