Chevy Impala SS Forum banner

Car doesn´t run ok

3K views 28 replies 10 participants last post by  4DoorSS 
#1 ·
I drove my 96 Fleetwood today for the first time in 6-7 weeks. I stopped at a gasstation and then I noticed that the idle was rough. I drove back home again and the car didn´t respond to 100%. Halfway home doing 50mph it seemed ok again and when I stopped at home the idle was fine. The check Engine light came on but is there something I can check Before I let a shop read the codes?
I could be mistaken but I thought I smelled quite strong exhaust fumes in the car the first 7-8 kilometer.
 
#2 ·
#3 ·
sitting the gasoline may have some water in it . after you drove it the bad fuel at the bottom of the tank may have been consumed . If you do not use this vehicle often always use fuel stabilizer ..

my guess p0300 codes . buy a scan tool cheaper in the long run rather than paying a shop to pull codes. $200 USD will get you a good scan tool diagnostic . OBDII.........
 
#4 ·
You can get the codes pulled at a local parts store for FREE. Check with Autozone, Advanced Auto, and O'Reillys. If you do not pull the codes, anything anybody says is speculation.


Unless you are in cold weather, contaminants (mainly water) in the gas is unlikely.
 
#6 ·
The onboard HVAC console will not pull every code. I'm certain you're dissecting the Stickies and searching 'stumble'. I would take the fact that it's intermittent as a plus in diagnosing.

Tiny farts of thought:
fuel canister purge: hoses - starting at tank, or solenoid.
Fuel pump or burnt harness sending you early warning.
EGR.
Humid OPTI
Broke ex man bolt
Mouse nest in First Base
Generally dirty injector(s)

But that's just me. GLWF
 
#8 ·
No matter what, the chances of a car having bad gas is minimal, and I would look elsewhere for the issue. The issue does not indicate low quality gas, especially since it threw a code. The code is the indicator, and will lead to the solution. The OP should pull what codes the HVAC module will extract, and look into the codes he gets for a solution. If it does not pull a code, then he at least knows that it is beyond simple diagnosis, and needs to take it to a mechanic, to determine what the code is, and how to fix the issue.


After pulling the code, he should erase it, and see if it comes back. It may have been a one time glitch.


You are probably right about not having the parts stores in Sweden (did not read the location). That does not prohibit him from pulling his codes through the HVAC module on his own. The first order of business is to pull the codes. Once those are available, maybe some accurate help will follow. No need for chasing a bunch of WAGs.
 
#9 ·
I don´t Think it´s a gasproblem. I drive on 6 months old gas every spring after the car has been sitting in my garage during Winter.
I charged the battery last night (for the 5th time this year). It gets drained since I don´t drive that often. I checked the battery with my smartcharger today and it showed empty although I fully charged it overnight. The car started right up though but I trust my charger more than the battery. It´s probably too easy but do you Think a bad battery can cause the problem?
 
#10 ·
Most chargers read your alt condition, so it's relatively easy to rule it out as the problem. You can try desulficating your battery. I've heard newer cars don't like running with NO battery connected, but never heard a bad one affecting operation once running as long as there's at least something hooked up. Be glad to be told different though.

You need those codes. How many KMs on your Cady?
 
#11 ·
Ok this is going to sound crazy. I had this happen on my Fleetwood. It had no power at all and would smell fat at idle. The part that fixed this condition was a new temp sensor on the front of the water pump. the computer was reading a -40 degree reading on the sensor and was dumping fuel at idle. replaced it now it runs great. simple fix
 
#12 ·
I tried the ACC in diagnostic mode and got a few codes.

-01 CCM Diagnostic trouble codes: Code 122

-04 ABS TC Diagnostic trouble codes: Code 27

-24 Coolant temp: Code 17

I can´t read them all though using the previous posted link. I used the most common:


Here are the most common you will need to know

-00 PCM diagnostics codes
-01 CCM Diagnostic trouble codes
-02 HVAC Diagnostic trouble codes
-03 SIR Diagnostic trouble codes
-04 ABS/TC Diagnostic trouble codes
-06 Engine RPM
-14 Vehicle speed
-24 Coolant Temp (°C) - Reading taken at the Water Pump sensor, This is what the PCM uses to control the fans.
 
#13 ·
I tried the ACC in diagnostic mode and got a few codes.



-01 CCM Diagnostic trouble codes: Code 122



-04 ABS TC Diagnostic trouble codes: Code 27



-24 Coolant temp: Code 17



I can´t read them all though using the previous posted link. I used the most common:





Here are the most common you will need to know



-00 PCM diagnostics codes

-01 CCM Diagnostic trouble codes

-02 HVAC Diagnostic trouble codes

-03 SIR Diagnostic trouble codes

-04 ABS/TC Diagnostic trouble codes

-06 Engine RPM

-14 Vehicle speed

-24 Coolant Temp (°C) - Reading taken at the Water Pump sensor, This is what the PCM uses to control the fans.

I would suggest you run the PCM codes, if any.

They are accessed from -00. Are you saying you have no PCM codes?
 
#14 ·
Just to clarify, when you see "-00", that doesn't mean you have no PCM codes. It is telling you the CCM is in the mode to access them.

In the Roadmaster, you then need to press the "middle" button to access them.

The "middle" button on the roadmaster HVAC panel is ironically on the top right.
 
#15 ·
Hmm I might have thought that you started the diagnose on -01:| Can´t remember if I ever pushed the "middle button" in -00. I will try again tomorrow just to make sure.
 
#16 ·
Ding Ding Ding -24 coolant temp. was it really that cold that day...replace the temp sensor in the water pump. :)
 
#17 · (Edited)
I'd hold off on that. That's not the displayed temp.
 
#21 ·
Hard to diagnose, but I'm leaning towards EGR circuit. Often doesn't set a code and symptoms very much include rough idle, stumbling at low rpms. Not really a factor at higher speeds while cruising.

Sometimes you can clean the valve, sometimes they just fail. It could be the solenoid, could be the vacuum tubing.


Good luck
 
#22 ·
I had the codes checked today and it seems to be something wrong with the oxygen sensor(s) or the cable leading to it. The check Engine light is off now and the car runs fine all of a sudden!
 
#23 · (Edited)
Fine. Did the code say which side? And don't know about EU, but in the States all '96's have 4 sensors.

While it's running well I would have a friend in the car and you underneath wiggling all the O2 sensor wiring to see if you can get the code to set again. Also, O2 sensors have a habit of wearing out and can affect running even without setting a code. General wisdom over here is BOSCH is a less-preferred name. ACDelco seems to be more robust for our cars.
 
#24 ·
I had the same idea but I rather have the friend underneath the car:) But 4 sensors??
 
#25 ·
Yes, 4 sensors. The front 2 are the ones that control the mixture, and the rear 2 monitor the function of the cats. The ECU knows which side they are on. All of them should set a separate code if the reading/functioning shows a discrepancy. They are not all easy to remove.
 
#26 ·
Thanks Fred. Bad memory edited above. And roger dodger on removing sensors. I'll put a few minutes into it, but if they don't come free right away with some heat and the special socket, then I just go ahead and remove the cat and attack it on the bench. Mattia, a thread chaser is good to have in reserve too - BEFORE you need it.
 
#28 ·
the O2 sensors of this type based on the manufacturers of this type O2 sensor is 100K miles however if the O2 sensors are 10 plus years old and in a corrosive operating environment they should be replaced due to corrosion on the base socket of the O2.

on O2 sensors with this vehicle due to the material GM used a 20 yr old sensor will require a good amount of torch heat to loosen and a thread chaser to clean up the exhaust threads fitting.

the proper placing of the wiring does cause problems and changing the O2 sensors will cause issues if you or the tech screws up the wiring placement.

since these components sense the engines exhaust for proper fuel combustion checking the fuel trims should be done periodically to save on fuel costs and cat converter damage.

checking the fuel trims before and after the replacement should be done.

on newer GM vehicles this O2 removal is not a problem and corrosion appears not to be an issue.

most 1999 plus GM truck engines the sensors are replaced at 130 K miles .
 
#29 ·
It's worth mentioning....if replacing the O2's, stay the hell away from Bosch sensors. Only run the AC Delco sensors and you can usually find them for a good price on Amazon.
 
  • Like
Reactions: j cat
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top