I need help asap
Thread Starter
Teching In
Joined: Apr 2017
Posts: 15
Likes: 0
From: Avon Park, Fl
I need help asap hey guys, I have a 1998 z28 ls1 that is completely bone stock with 150k A4. My car started act up really bad at idle and durning take off. it feels like its misfiring like crazy. I checked for codes and the codes are P0157, P0138 and P0300. I looked at my fuel trims when the car is acting up and bank 1 long tirm and short tirm are good but I noticed that bank 2 long and short tirm was -30. But if you give it gas and it stops acting up. Bank 2 fuel trims are normal. On take off it sometimes stalls or it will surge really bad. Ill be WOT (durning take off when the car is acting up) and Rpms wouldn't even move and ill just let it idle and I'll tap the gas and it'll take off. And I used my friends snap on scan tool and saw when the car is acting up. All the cylinders on bank 2 start to miss. And it only happens at idle. Once your driving the car runs awesome and and will WOT like nothing is wrong. But once you come to a stop the car will sometimes act up. What do you guys think will be causing this .any help will be appreciated. Thank you
Last edited by Antonio Barco; Jun 6, 2017 at 10:41 PM.
Joined: Nov 2001
Posts: 34,631
Likes: 2,553
From: Schiller Park, ILL Member: #317
Good advice. Since the issue seems to be bank specific, and with those codes and symptoms, I would certainly look at that front O2 sensor (or wiring) as the first step.
The reason the engine runs crappy at part throttle is because the bad 02 sensor(s) are dumping a lot of fuel and its crazy rich......as soon as you go WOT you dump a ton of air in there and its not rich anymore. Also, the MAF comes into play also when you go WOT to help make things right.
$45.00 for a new sensor and 5 minutes of your time under the car....and you're done. All you need is one crescent wrench.
And buy a Denso 02 sensor....A lot of PCMs will not operate with Bosch. Mine doesn't.......so why take the chance, pain in the *** to have to go get another one.
Rockauto.com usually has Denso 02 sensors for $35.00 - $45.00. Also, Amazon.com with next day shipping. I do find them in town locally at Advance Auto or PepBoys for like $45.00-$50.00. The dealerships will sell you a GM AC Delco sensor....but in the AC Delco box you will find a Denso sensor.......easily the best 02 sensor out there today.
.
$45.00 for a new sensor and 5 minutes of your time under the car....and you're done. All you need is one crescent wrench.
And buy a Denso 02 sensor....A lot of PCMs will not operate with Bosch. Mine doesn't.......so why take the chance, pain in the *** to have to go get another one.
Rockauto.com usually has Denso 02 sensors for $35.00 - $45.00. Also, Amazon.com with next day shipping. I do find them in town locally at Advance Auto or PepBoys for like $45.00-$50.00. The dealerships will sell you a GM AC Delco sensor....but in the AC Delco box you will find a Denso sensor.......easily the best 02 sensor out there today.
.
Thread Starter
Teching In
Joined: Apr 2017
Posts: 15
Likes: 0
From: Avon Park, Fl
Aren't p0138 and p0157 for the rear O2s? But either way ill repalce the front ones later this week. And hopefully fixes the problem. Thanks for the suggestions guys.
Aslo since the fuel trim on bank 2 is reading -30 .doesn't that mean its taking away fuel causing it to run lean?
Aslo since the fuel trim on bank 2 is reading -30 .doesn't that mean its taking away fuel causing it to run lean?
Last edited by Antonio Barco; Jun 7, 2017 at 07:12 PM.
Originally Posted by Antonio Barco
Aren't p0138 and p0157 for the rear O2s? But either way ill repalce the front ones later this week. And hopefully fixes the problem. Thanks for the suggestions guys.
Aslo since the fuel trim on bank 2 is reading -30 .doesn't that mean its taking away fuel causing it to run lean?
Aslo since the fuel trim on bank 2 is reading -30 .doesn't that mean its taking away fuel causing it to run lean?
Thread Starter
Teching In
Joined: Apr 2017
Posts: 15
Likes: 0
From: Avon Park, Fl
I checked the spark plugs on bank 2 and pulled the spark plugs on bank 1 and they all look the same. The car threw other code .P0108 and when it threw that code both banks were at -15 long tirm and short tirm for both banks were -30
Trending Topics
Two things that are worth knowing when dealing in NB O2 sensors
1. When I suspect one is bad, I unplug it. Disabling it means no more fuel trims for most ECU (most cars). That means if the O2 sensor was feeding bad info to the ECU and the ECU was "learning" the bad info, all that bad info (incorrect fuel trim) should go away when you unplug it. In other words, Unplug the sensor and see if now the car seems to run better, and a/f ratios are better. You should have a wideband anyways (which would immediately inform you of a bad O2 related fuel trim).
2. Any Narrowband O2 sensor from nearly any car in the world can take the place of any other NB O2 sensor. You don't need to spend big $$ for one, especially just to test it. When I need a narrowband, I walk down the aisle of the local discount auto store and find the cheapest, whether its 1, 2, 3, or 4 wires, It will work. Simply wire the signal wire to the ECU and it will work, even if you leave the other wires disconnected (they are just for heating the sensor).
1. When I suspect one is bad, I unplug it. Disabling it means no more fuel trims for most ECU (most cars). That means if the O2 sensor was feeding bad info to the ECU and the ECU was "learning" the bad info, all that bad info (incorrect fuel trim) should go away when you unplug it. In other words, Unplug the sensor and see if now the car seems to run better, and a/f ratios are better. You should have a wideband anyways (which would immediately inform you of a bad O2 related fuel trim).
2. Any Narrowband O2 sensor from nearly any car in the world can take the place of any other NB O2 sensor. You don't need to spend big $$ for one, especially just to test it. When I need a narrowband, I walk down the aisle of the local discount auto store and find the cheapest, whether its 1, 2, 3, or 4 wires, It will work. Simply wire the signal wire to the ECU and it will work, even if you leave the other wires disconnected (they are just for heating the sensor).
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thread Starter
Teching In
Joined: Apr 2017
Posts: 15
Likes: 0
From: Avon Park, Fl
And I forgot to mention that it happens intermittently. Like it hasn't acted up all day today and like I said in previous post that it threw code p0108 .I looked at both banks 1 and 2 fuel trim and they both read -30 and I tried to WOT and it didn't do anything. Didn't even try to move and it stalled
I feel like -30% fuel trims should be a lean condition not rich. Am I trippin? If it's attempting to pull 30% fuel and is still rich....that a separate issue. If unplugging o2 sensors doesn't help I'd look elsewhere. If its successfully pulling 30% fuel then WOT should be normal because negative trims are ignored at WOT. Right?
Thread Starter
Teching In
Joined: Apr 2017
Posts: 15
Likes: 0
From: Avon Park, Fl
I checked fuel pressure when the car is acting up fuel pressure was 68 psi constantly but I did notice when the car was acting up vacuum was going down and and when it was about to die .I tried to give it throttle but then the vacuum hit 0 and it stalled. When the car is not acting up .vacuum is around 17 to 19 in.hg