2008 LC200 sometimes bucking when going uphill

[Tundra61]

Hey all,

I have a 2008 LC200 that sometimes bucks when going uphill. It is an occasional problem at both high and low speeds - it does not always do it. It was doing it 5 months ago but after taking it to the dealer they thought it was just a bad coil so we replaced the suspect coil and all plugs. Since then it didn't do it until the other day. When it does it - the dash lights up with the following (I think) - tire warning, crawl control, center diff lock indicator and maybe ABS. Not 100% - going by what the wife said since it's her car!

So, has anybody experienced a similar problem or thoughts on what it could be?

 

[Tundra61]

Just did a test drive and was able to make the stumble happen - the check VSC message also appeared. So, assume that's the cause. Any ideas how to resolve?

 

[chilibit]

VSC piggybacks on lots of issues. I would read the fault codes to start. Is all this on a single tank of fuel and was the tank level low?

 

[ceb]

VSC piggybacks on lots of issues. I would read the fault codes to start. Is all this on a single tank of fuel and was the tank level low?

I hope he's not on the same tank of gas from 5 months ago but you bring up a very good point. The issues may not be the same as a half year ago. Was the failure last time also accompanied by a whole Christmas tree of lights?

Years ago I had an issue where my Yukon would periodically refuse to start. It would crank, but nothing. I'd get it towed to the dealer and it would start. This happened two or three times and always left me stranded in the strangest places - parking garages, airports and so forth. One time it wouldn't start in the parking garage at my office. The tow driver came, tried to start it, nothing. Towed it out of the garage, tried again, nothing. The second tow driver came (the first one was only there to get it out of the garage) and nothing. Towed it to the dealer and it started right up coming off the truck. It was diagnosed as a bad fuel pump which solved the problem for a half year. Then I started getting a bit of stumbling going up hills (between Frederick and Hagerstown on I-270 for those of you that know MD). I could replicate the problem every single time on the same stretch of road. Turned out it was a bad cable from the coil. It was an aftermarket ignition system I had installed 70k miles earlier. I went back to the OE cable and all was well. In retrospect it may never have been the fuel pump after all.

Yep, pull the codes and go from there.

 

[chilibit]

Uphill specifically or under load?

 

[highrisk]

If that happened to me I would be suspect of my plugs and coil packs. It sounds like a classic misfire. The question above is right on the money. It should do it going up hill and under load.

 

[mark71]

What code did it throw?

 

[Tundra61]

I don't have a device to check the code but it does it mostly when going uphill and under acceleration. Earlier in the year the dealer said it was cylinder 1 misfiring so I replaced that coil and all the plugs. No problem for about 3 months and it then happened again yesterday.

 

[NetJunky]

just curious why you only replaced 1 coil? usually when 1 coil is going out, the others are to follow. I know replacing all 8 coils is expensive but they usually all go out around the same amount of miles. How many miles do you have on your odometer?

 

[jtwopark]

do you have oil leaking from the spark plug tubes?

 

[mark71]

do you have oil leaking from the spark plug tubes?

Agree with checking this: pull the coils and check for oil on them as well as directly visualize the plugs. There is a rubber gasket around the spark plug tubes where the valve cover meets the head. I have a slow leak on one of mine and it is one of the known problems with the 5.7. If it is filled with oil (very bad leak), that might cause some problems.