QuestionThanks for the quick reply! The code number for the misfire is P0300. I was looking thru all my invoices from this car and how many times I took it in complaining of these problems, so much money spent to be told everything checked out ok by the computer, even the dealership sent me away saying the floorboards were fine, you couldn't even keep your feet down on that side! I know nothing about cars but I could even piece some things together. Will it be hard to find a mechanic with a Tech 2 scanner, I won't go back to the dealership. I don't think the obvious parts were checked but I could be wrong. Thankyou so much I was beginning to think I had a lemon! -------------------------
Followup To
Question -
this is the order in which things happened
service engine light went, diagnosed as misfire on a cylinder. Towing, service engine light went on, recommended to change all spark plugs and wires. Towing again car overheats extremely on passenger side floor. catalytic converter tests normal.new sparks and plugs, heat diminishes but service engine light returns. Popping sound from gas tank area after 1 min. of driving then again after engine is turned off, very loud! Car now shudders when towing over 50 miles per hour. Car is a 1999 Chevy Tahoe we have all regular maintenance done, use premium gas, change oil every 3000 miles, no one has been able to help on this! Thanks!
Answer -
Hi Julie, I had a 1999 tahoe with this exact problem. First, you will need to contact your dealer to ask if there is a PCM (Powertrain Control Module) update for this problem, which is what cured the problem with the first Tahoe like this that I ran into. The update will need to be done by anyone who has a Tech 2 Scanner and who has subcibed to the update information to do this. The updates are simply changes made to the pcm (powertrain control module) such as adding more fuel or changing ignition timing and so on. The cost for this is usually 1 hour labor rate, any more than that and find another place to have this done. If there is no update for your vehicle, which will be determined by the vin# of your vehicle, then there are other problems. The second Tahoe I cured with this same problem had a bad valve in cylinder # 4, not really a cheap repair, but that will need to be checked by a technician while watching the valve operation with the valve cover off, the compression check was within specs during the test, but with the engine running under load, you could see the valve wobbeling around, again, all checks were normal during the compression and leakdown test but was only found by looking at the valve operation under high RPM. Another possibility is a bad fuel injector, but i have not run into any problems with this type of injection system as of yet. If none of this helps you, please let me know and i will give you my phone # and we can talk about this in depth, or, we can continue as we are now on this site. I also need to know if there are any other DTCs (diagnostic trouble codes) that showed when you had the vehicle computer scanned, if so, i need the number of the code or codes. Also, have you checked the obvious parts such as the ignition coil, fuel filter, and fuel preasure, those would certainly cause a misfire code, also, which cylinder is misfiring? A good scanner will let you drive the vehicle while watching each cylinder for a misfire and will store the number of misfires and which cylinder was misfiring. The converter is heating up because there is too much air going into it, which is caused by the misfire, this will also cause a backfire in the exhaust system when turned off.Please get back to me for i will stay with you on this until the problem is solved. Also, I would ask you to get back to me when your vehicle is repaired and what the problem was so that I may enter it into my data bank so that it will help others also, Thank you Julie, MANFRED
AnswerHi Julie. I sent you a response yesterday ( Monday) concerning AC Delco Service Centers, but when I tried to send this, I said that this page was not available, so I'm not sure if you received this E mail. Please let me know if you didn't and i will retype the response and send it again. Sorry for the delay, but I tried 3 times and each time I received the same message.
