Ag E55

Ok, I am in hopes that someone can shed some light on to my situation...about a month ago, I started to get CEL, found out that I was having cylinder7,8,9 were misfiring....gone through whole bunch more test and came to conclusion that I needed to replace, the left bank coil pack, wiring harness (due to oil leak), o2 sensor, MAF sensor, plugs, and injectors.....after almost $5K in repair bill, it still misfiring in cylinder 8 and 9....I am totally lost here and so is my mechanic.....any advise would be hugely appreciated it. Help out a fellow member please...any certified technicians out there with some idea?

Thanks in advance.

AH1W-COBRA

it looks like your mech tried to eliminate anything that would cause the misfire.did he verify the voltage signal to the injectors?.the fact that you picked up one of the down cylinders but replaced more than that specific injector leads me to question the injector harness or the signal it transmits.all the parts you have replaced are related to misfire other than O2 which was probably damaged from a rich,miss fire mixture.ALL good mechanics keep learning all the time.You might consider taking it to a dealer where they have access to the electronic troubleshooting equipment to "pinpoint" the issue.and if it stumps them they have access to regional reps,than the factory.the amount of skill and experience the dealers have cant be disputed.im eliminating spark from the problem based upon the simplicity of determining if it is present and timed correctly,plus you replaced the suspect parts.this entire issue could be caused by a engine management computer,tough for your ind mech.dont flog your mech,just let him know what it turned out to be.

Ag E55

I guess that is something that we haven't looked into....I will take it to the dealer and see what they find. I know what you are saying about the situation that a typical ind.mech is in...i like my guy, he is a great guy...but the frustration is simply that i have spent a fortune and nothing has improved....just hate the thought of going to a dealer and getting ripped off.....thanks again for your input, I have seen few of your posts and comments and you seemed very informative on the subject matter. thanks again and will post the results.

AH1W-COBRA

i only take our cars to the dealer when it is a situation like yours.their labor rate is high but you cant let yourself think that they will intentionally rip you off.I am loyal to MB of escondido,Nate is a great SA and keeps you informed.they would not want to get caught padding time/parts falsely,i dont believe they would even consider it at MB escondido or fletcher jones.hang in there,fix it and put it in the past.

Ag E55

Well, I took your advise and took the car to the dealer yesterday, had a lengthy discussion with the service advisor and they seemed to think it would be a simple fix. They are having their shop foreman personally work on this car. It turns out that they knew all about my problems, since my indy mech has worked for years there and he has been calling there to get input while he was working on my car. I am in hopes that I get the car back today.....will let you know what the issue was. Thanks again for your advised and direction.....your willingness to share your knowledge and experience is the true essence of these types of forum.

Ag E55

Well, after 3 days at the dealer and $1200 later, it turns out that the problem was the dirty fuel caused fuel injector to be clogged with some debris.....they took off the fuel rail and dumped it in to clear jar and saw some debris. They did this because the injector interval on the left bank was bit more irregular than the one on the right bank. So, they replaced two o2 sensors, 3 injectors.....now the car purrs like it should. Wow, the total cost for all this has been absolutely frightening......a $6,800 total! Absolutely scared of driving the car now.

AH1W-COBRA

your mech thru alot of probable fixes at the issue,he was close in the fact that he suspected the injectors,who would have ever thought to be so simple as debris in the fuel rail/injectors.fuel filters should prevent that.it is so hard somtimes for mechs to start with the most simple non component related cause such as contaminated fuel.he would have to R&R the fuel rail just on a hunch that their might be contamination.9 cylinders fired and 3 did not.i would have suspected electrical myself.you and your mech have built alot of reliability into the car and you wont have to worry about the new parts failing fo along time.

Ag E55

I totally agree with your perspective....I don't think I can blame him at all, but the fact that I had to put so much money out of packet is what bothers me. Even with the dealer, it took the shop foreman 3 days to come to this conclusion...the car runs better and it passed DEQ, but I can still feel bit of misfire...I am taking the car back to the dealer in the morning. They will probably want me to change out the fuel filter this time....where is this going to end? I must admit, when the car runs properly it is absolutely amazing.......so here I go agian, maybe I am being too particular, but the car has to run properly, don't you think? Thanks again for all that you have shared...I will keep you posted what they find next.