chevyluver

Any Ideas on what could be making this occur?

smiller944

My name is Steve, and I have the EXACT same issues as brianSW...however I have just begun my problems on a 1996 Chevrolet Tahoe 5.7l (350), 150k mi., one owner, never had an issue. mechanics have no clue but to start replacing things and see if they work...only codes so far are "random misfire" and O2 voltage low on bank 1 & 2...sensor 1. I had run several cans of seafoaam through the system and it worked for a while...then.... cap & rotor, wires, plugs, fuel filter, etc. Fuel pressure was OK (so I was told by dealer), I guess I'm at the point that I'm ready to start throwing money at it and do the work myself, and would like some advice...maybe from someone thts been there. Can I get any attention/direction from someone who knows better???? Off the top of my head I'm thinking..........Fuel system.......Fuel pump? EGR? Vaccumme leak? injectors? What else could show/cause O2 sensor failure on new sensors??? But I don't have a clue..... This problem has just started in the last month but is getting worse by the trip... once last month in 2000 miles and now every 100 miles or less. The dealer nearby is willing to "do as I ask" if I can tell them where to start...and where to go. If anyone can help......Thanks!

chevyluver

I had the same problem on my 2000 s10 4.3l, it turned out to be my fuel pump(that I had replaced 9 months earlier). I would definetaly re check the fuel pressure. I hope you can figure out your problem, be sure to post back and i'll do my best to help you out.

shell51

I have a 2000 blazer and my story is the same as yours to the T.after putting in a new engine i replace my fuel pump twice already.other parts that have been replaced include mass air flow sensor, ignition coil (TWICE), ignition module (TWICE), crank sensor and shims, pcm, fuel pump relay, battery,4X4 switch and still have the same problem and its getting worse. I guess i will try looking a the distributor next.oh and my catalytic converter has been taken off because it was all clogged up. it runs a little loud but that's ok. My check engine light is always on (I was told that's because the catalytic converter) and the abs light comes on periodically.my dash lights come on and go off when they feel like it, my ac button has a little blue snow flake on it which should always be lit up and when you choose to use that button a small red light shines next to it to tell you it is on.well this little blue snowflake does not light up and the ac does not even come on when you push this button. sometimes i feel hot air at my feet in the drivers seat when i am driving (and the heater is not on).and last but not least when I turn the ignition key most of the time my back hatch window pops open.hows that for fun? anyone know what i can do to keep this car running from point a to point b without calling a tow truck all the time? a friend of mine is haveing the same problems with her Bravada. we have both spent alot of money to find out whats wrong so if anyone can help us that would be great!

DHoShow

Wondering if this is resolved for anyone? OP why did the dealer say that it could be leaking injectors did they tell you? If they are leaking fuel into the combustion chamber then perhaps that is the cause of the misfire, which fouls your O2 sensors with a rich exhaust. Then the engine goes into limp mode, only giving you enough power to barely move.. anyway that is probably the reason for loss of power, the failing of the O2 sensors.. but yeah they prob wouldn't all go bad at the same time by electrical fault

inthechateau

Been reading this thread with great interest as my 96 Tahoe just started to act similar. On a 2000 mile trip when pulling long hard upgrades SES light and loss of poer occurs. Turn off engine and restart and all is fine until that big power demand is asked of it then right back to safe mode. i am thinking furl pump or loss of fuel pressure. Can someone correct me by I am hypothisizing that loss of fuel pressure is causing a lean mixture, lean mix is causing O2 sensors to trip with Hi or Low voltage signals. I put a fuel prssure gage on it and have not tried to drive it whilel looking at gage, but that is next test. Not thinking blocked CAT as it runs like raped ape at first and only shuts down after long hard pull. I am getting 60psi at start and constant 50psi while running. Three DTC codes P0131, P0151, and P0138. I replaced the Bank 1 sensor 2 due to the P0138 code and it was still tripping that code after replacing it.

96 Tahoe
4X4
5.7 R code
262,000 miles
AT

Steve73

I have the same problem! Please help!

nvandale

Soubds like a loss of back pressure. Most likely a leak in theexhaust manifold close to the block.

ds12short

A couple of more things I would check.
1) Restricted intake. How's the air filter? Another thing that happened to mine was I have a corrugated hose on the intake (1994) and when you needed power and stepped on it the hose would collapse and restrict the intake air. Took off hose and it ran like a champ. Put on new one of course.

Called fresh or cold air intake hose. Also look for rips in hose. Good luck

Robert Coster

had the excact same issue and it was the sensor inside the distributor cap. just replaced it and drove cherry after that.