This is my first post to this site. I'd like to start by expressing my appreciation to everyone in this forum. It's been a life saver in the past when my headlamp went out and when my 6-disc changer wouldn't spit out any of the *seven* discs that were stuck in it!

I have a 2003 CL, automatic with > 150K. I perform the oil changes and regular maintenance myself every time it comes due.

About a year ago, my car started presenting problems when I tried to start it. It would turn over, start, then shudder hard enough to shake the car for a few moments before I began to drive. In the past few months, the problem has gotten much worse. Sometimes the car doesn't start at all and when it does, it shakes and shudders, some times stalling. If I do get it to start, the shuddering begins as soon as I put the car into gear. I have to drive for a while before it returns to normal driving. When I reverse from the driveway, it acts as if the fuel supply is being cut off when I depress the gas pedal. Some times this causes the car to stall. I have more problems starting during lunch time (after the car has been driven that day) than in the morning when I first use the car. I seem to be able to reduce the shuddering if I start the car and let it run in park for 10 minutes before I take off, but this isn't always practical.

A few things to keep in mind: my spark plugs are all in good condition and the ignition coils were replaced within the past few months. I always use 93-octane gasoline and have recently switched to Shell.

I made the switch to Shell because I received a letter from my other gas station, which I had been going to for at least two years, saying in effect that their tank had been contaminated and some users of the 93-octane gas were experiencing problems with their cars. They offered to reimburse me for repair expenses.

I would gladly take the car to the dealer then ask for reimbursement but I don't have the money for the repair to pay upfront. Receiving this letter has lead me to think my problem lies with the fuel delivery or a related system.

Also, I have tried cleaners like SeaFoam with no results. I plan to clean the IAC valve later this week and hope that will help. Any suggestions will be greatly appreciated. Thanks!

 

I forgot to include something important in my post.

When I have to accelerate hard from a low speed, I some times feel the hard shaking and there is a lag before the car accelerates. Codes P0300 & P0301 (Cylinder Misfire) are given (along with another cylinder misfire code, I forget which cylinder). If I clear the codes, they don't come back until I have to do another hard acceleration.

Thanks again, guys.

 

Could be problems directly related to the bad fuel. You sure the spark plugs are good?

 

I'm pretty sure. My father looked at each one and said they're good. He has lots of automotive experience.

I cleaned the IAC valve on the outside part by removing the tube from the air filter. I wasn't ready to take the whole thing off by myself. I'm not noticing an improvement. It still shudders when I start it but it seems to be better in cold weather (it only recently got cold here in south Texas). Also, I noticed one of the hoses attached to the tube was missing its clamp so I put one on to form a better seal.

If you think it's the spark plugs, is there a way I can check this without buying a whole new set?

Thanks again!

 

No improvement today. I has trouble starting and god codes P0300, 0301, 0302, 0303 and 0304. Any suggestions on what my next step should be?
Thanks again guys.
mh

 

Might be the coil packs too. One bad coil pack would cause the other cylinders to misfire. Check the coil packs by unplugging each one at a time to see if the engine changes tone or how it runs. You can also use a voltmeter to check the resistance in the coil packs.

If you pull the plugs and they look good and none of them are different then the others then it probably isn't the plugs.

 

I'm suspecting a fuel delivery problem. I've seen no improvement by cleaning the IAC valve. I suspect fuel delivery because I no longer hear the fuel pump come on before turning the key to start. On most days, the car doesn't refuse to start until the third or fourth start. The first start of the day usually works but with a bit of fuss. I also get codes for misfires on cylinders 1, 3 and 6 still every so often (not while starting but while driving). Could I have a fuel pump that only works part of the time? Dirty fuel filter? Maybe a problem with the fuel pump relay. To be sure to eliminate the ignition coils, should I move them to different cylinders and look for different misfire codes?

Thanks again so much,
mh

 

while trying to leave the place from where I last posted, I had much trouble starting the car. It took almost :30. It would not start at all (it turned over fine) so I let it sit for ten minutes. I tried again, it started about five or six times and ran for only a few seconds before stalling. I finally got it to start and stay running long enough to put in into gear and drove home. It sputtered much for the first few blocks and produced misfire codes for all six cylinders. Now I'm really suspecting a problem getting fuel to the engine. Any new thoughts?

Thanks always,
mh