Question about 2002 Chevrolet TrailBlazer
I had several code errros. just changed the exhausted acuator sylnoid and both O2 sensors. Its better, but I have to drive in 3rd in order to get to 55 mph and there is a loud whistling noise that starts at a slight load and gets louder. If I push it, it will throw a code for O2 sensor and misfire on #4.
Not sure why you have changed the parts you have already changed and if you have changed this stuff due to the same codes. Am guessing that the misfire code you are getting is P0304 since you said a msfire in number 4. Now as far as the O2 sensor code you're getting could be a number of different codes depending on what your computer is detecting. I guess what I am getting at is that you hear a whistling noise which could be a vacuum leak but not there to hear it myself. If your O2 sensor code is saying that your vehicles system is running lean (PCM has lower voltage readings 100 mv is lean & 1000 mv would mean rich running conditions so if able check your freeze frame data in your scanner). If running lean then to much air is being detcted which the main cause for that is usually a vacuum leak. A vauum leak can cause a code of a misfire. In most cases a P0300 (multiple misfire) but not in all cases. I may be way off base but you mentioned whistle and the other things so not being there this could be the case and thought I would throw in my input.
Posted on May 03, 2013
a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
New users get 2 Free calls (no credit card required) and instant help on almost anything you can think of (from cars to computers, appliances, handyman, and even pets).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
SOURCE: knock in engine
Check your timing belt too, it might be loose already. My car had the same problem and thougt that engine was going bad on me. Tried also the additives but didn't help. So I did a litle invistagation to figure out where the knoking sound is comming from. It sounded near where the belts are. Opened the cover and voela! found the belt was loose - took it out - upon invistegation, belt was starting to wear out out - one of the teeth was starting to peel off. Replaced it, retightend it and replaced the belt tensioner too - so far it's been 4month now and still no knocking problem.
Hope this helps..
Posted on Sep 09, 2008
SOURCE: O2 sensor problem
I have a 97 gmc sierra .This truck is the same as the chevy ok.Its a 350 5.7 liter 4x4 Z71.I took it to auto zone which was my first mistake.They put it the scanner and said bad O2 sensor.Ok so which one is it i said.They dont know.Well there four (4) O2 sensors in this truck i hope you know that.I had to replace all four of them before i had to take it to a real shop.It seems the fuel pump i replaced a week earlier with an auto zone fuel pump was bad.Ive changed my feul pump 4 times now and have 235000 miles on still running.You need to get your fuel pressure checked.It should be 65 psi to start it and 55 psi to run it.If the pressures are good it could be a different O2 sensor or maybe the mass air flow senor.My last option would be the fuel pressure regulator because it seems to be a waste of time and money.I would get that fuel pressue checked first.Good luck.
Posted on Nov 25, 2008
Could be coil pack(s), fuel injectors, etc. Rather than retype it, just check out this great article on P0300 random misfire - http://www.obd-codes.com/p0300
Posted on Dec 15, 2008
1- check there is spark come from spark wires
2- check the fire timing by looking for every wire in the right place
3- check there is injector signl
4- check for any vacuom leak
5- try to clean the MAF by brake and parts cleaner
6- try to reset all the code and see what will come after that
Posted on Mar 14, 2009
Tips for a great answer:
Nov 30, 2015 | 2004 Chevrolet Classic
Jul 28, 2015 | Cars & Trucks
Jun 28, 2014 | 2002 Honda Accord
Feb 21, 2014 | Pontiac Cars & Trucks
Aug 28, 2013 | Kia Spectra Cars & Trucks
Mar 16, 2017 | 2002 Chevrolet TrailBlazer
Mar 12, 2017 | 2004 Dodge Neon
Dec 11, 2009 | 1999 Chevrolet Tahoe
Oct 06, 2009 | 2000 Hyundai Accent
Jan 15, 2009 | 2002 GMC Envoy
63 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: