1997 q45t question, Please help

[Wilky]

I have a 1997 q45t with 188,000 miles. About 30 days ago, I was driving to work and the going up a hill and the check engine light came on and the motor really bogged down and felt like it was missing going up the hill. So I decided to get some bg44k fuel injector treatment and run it through the tank and the problem cleared up and the car started to run much better. The codes at that time were the two knock sensor codes with circuit failure. So I reset the codes and about a month later it happens again only this time, it has the two knock sensor codes, with a misfire on cylinder 2. Where should I start, Could a coil pack be bad on cylinder2 and cause the knock sensors to trip. Please give me some direction. I bought the car with 110,000 miles. It had always had dealership service in Austin, Tx. Since, I have owned it, I have had all of the fluids changed. Then spark plugs, oxygen sensors, valve cover gaskets, Belts, etc. plus all of the routine oil changes, air filters, fuel filter, etc. I have not done anything beyond that.

THanks

Dan

Modified by Wilky at 1:37 PM 3/7/2009
Modified by Wilky at 1:38 PM 3/7/2009

[maxnix]

How about some maintenance history? Sparkplugs? Fuel filter? Premium Tier1 always?

[Wilky]

I updated my post with some maintenance history.

Dan

[maxnix]

Well, we not only need to know what but also when. For instance, it should have had about 6 or 7 fuel filters since you owned it.

Do you have ethanol in your fuel?

[Wilky]

I have put 4 fuel filters in it. I just bought one last week, but have not put it in. Also, I do think some stations that I have purchased fuel at do have ethanol in their fuel. However, the one that I go to most does not.

[maxnix]

Change fuel filter. Use a few bottles of Iso-HEET in your next few tanks and some BG44K or Redline SI-1 and report back, please.

[maxnix]

If you are not using OEM filters, be sure to stock up on filters (engine, cabin, fuel and M1 oil) and spark plugs (your hsould be on your 3rd set) from Joe while he still has an addtional 7% off next week.

http://www.infinitipartsusa.com

Call and tell them you are from NICO.

[bullittandy]

Please excuse the previous 3 posts which do nothing to solve your problem. (WTF Brian? -You know the answer here-just tell him!)

Coils on these cars go bad all the time and you got lucky that you found the specific cylinder. Replace the coil and the knock sensors and your car will run great again.

good luck!

[maxnix]

Please excuse the previous 3 posts which do nothing to solve your problem. (WTF Brian? -You know the answer here-just tell him!)

Not sure if there has been enough information to justify the conclusion that a coilpack has completely failed, yet.

[bullittandy]

There's plenty of info but you could have offered a guess if you wanted to be nice to the new guy who takes good care of his car.

[Wilky]

Well I installed the new fuel filter today and my old one was full of black gasoline. It appears as if I may have two problems. The bogging out and throwing a code is not happening any more, but I do still have what feels like a miss at about 2500 rpm driving down the highway. I can put my foot in it and it goes, but when I barely press down and slowly accelerate it misses or what feels like a miss and does not throw a code. So for now the fuel filter has made a big difference, I am going to have to put the redline si-1 cleaner in this week and see what happens; if it gets better. I will also watch where I buy gas at from now on. Thanks for all of the help. I will update after I run the cleaner through.

Dan

[maxnix]

I'd do Iso-Heet also. Keep running the SI1 through a couple of tanks and check the codes. You could have more that one problem.

The fuel filter is small, so you may want to buy a few more with other filters from Joe while the sale is still on this week. With ethanol, even changing every 9 months may not be often enough.

Like you say, buying Premium from newer Tier 1 gasoline vendors will help as there tends to be less gunk in the tanks. Once the UST start leaking, ethanol, mud and ground water is a deadly mix for your car.