97 sunfire poor power and rough idle

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jimtone

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My 97 Sunfire has lost power and doesn't want to shift properly. I got a diagnostic report that it has an oxi sensor mishap so I changed the front at manifold with no improvement then the rear sensor after the converter and the check engine lite went off but test drove to find it still has weak power and doesn't want to auto shift at proper speads? I changed both the crank possision sensor and cam possision sensor and the cat converter along with checking spark to all 4 plugs which are also clean and gapped properly. Air filter is new and plug wires are fine. all coil packs are fine also. I haven't found any vacuum leaks and don't know what to think at this point??
 
Did you test the fuel pressure and how long since you changed the fuel filter?
 
I forgot to list the diagnostic codes we got at beginning which are P0420 P0300 P1404
 
It's been 12 months since changing the fuel filter and I've not checked fuel pressure. Is that what the other 2 codes are for?
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http://www.obd-codes.com/p0420

http://www.obd-codes.com/p0300


Code 1404 Sunfire :

Code P1404- EGR monitor test failed.
The PCM expect to see engine speed drop as each of the three EGR
solenoids are cycled on during rapid deceleration.

Enabling conditions: Engine coolant temperature is
over 184°F. Oxygen sensor voltage is over 0.57 volts (indicating the system is not in decel fuel shut off).
Vehicle is in 1st or 2nd gear. Vehicle speed is over 20 MPH. A/C clutch is not engaged (turn off A/C and
defrost). Throttle position and engine load indicate the vehicle is in decel mode. The PCM will cycle each
EGR solenoid and watch for engine speed to drop.

Code P1403 is for EGR solenoid #2. The expected RPM
drop is 925 to 1063 RPM. Blocking action: None.

Testing: Apply a ground to the light blue wire (EGR
solenoid #2) to turn on EGR #2 solenoid. Engine speed must drop. If engine speed does not drop, check for
battery voltage on pink wire (EGR solenoid power) at the EGR. If the voltage is low, check the in line 10
amp fuse for the EGR solenoid. If power and control signal are normal and the engine speed does not drop,
remove EGR and check for plugged EGR passages or bad EGR.


Doug in P.R.:cool:
 
Are you saying there are more than one EGR solenoid on the engine? I changed the EGR that's mounted on the transmission end of the head, but it didn't make any change.
 
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I printed the 6 pages of diagnostics for the EGR valve and began the test procedures to hit the wall on the first 2 tests. I'm not getting any DC voltage on the middle C wire that is suppose to have 6 to 9 volts which sends me to test the D wire for 5 volts but only get 2,4 volts. Now it says this could be a PCM problem but suggests this is very unlikely to have a PCM shut down, but start checking connections?? I feel like I'm working on a Boeing 777 with all the technical crap? I towed the car to a shop that raves that they have a test terminal that cost 15K and two days later towed the car back to my home to start over. I can easily see why these cars just go to the scrap yard with these type problems!!
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You may be able to do an egr delete for testing purposes. Some remove the valve and install a dead plate. Haven't seen or read about sunfires yet, but maybe there is a guide somewhere. Caution---this may not be legal.
 
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GM put out a bulletin for all their cars for electrical connectors .

I would check each one related to the EGR.

Check you large computor grounds , make sure they are clean and tight, . usually mounted all together on a stud on the engine somewhere.

Other than that have a GM dealer scan it , about $80. ( at least they can tell what it reallly is)

Doug in P.R.:cool:
 
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I've tried checking the wire terminals on Map sensor and EGR with a multi meter set on DCV dialed to.20M and I'm not getting 5 volts on any of the wires? Someone told me I should start removing the connectors one at a time while checking the EGR or MAP wires for 5 volts, and I may find the problem is in another terminal/sensor. I've checked the only 2 ground connections on the sides of the engine that I can find for clean and tight.
 
I've removed every sensor wire connector one each and checked the DC voltage on the EGR wire connector and never got 5 volts from any wire on the EGR connector. I don't understand how or why I'm seeing less than 5 volts DC at all the connectors that are suppose to be 5 volts? I'll try disconnecting the output wire from the PMC and test those terminals for 5 volts DC? All my ground connections are cleaned and tight.
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Some connectors only provide voltage when the computer sends it. Does the egr receive voltage when the engine is cold. I don't have the answer, but it is something to consider. For an example, a lot of vehicles won't go into overdrive until the engine reaches a certain temperature. The overdrive system waits for the voltage or ground from the temp sensor. It is possible that the egr may not receive voltage until the engine heats up. You also have similar symptoms to jumped timing.
 
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The MAP sensor plug also isn't getting 5 voltd DC, and I'd think it should be getting 5 all the time if the key is on??
 
He's fun to watch, but I checked all the plugs for wear and gap first and have searched hard for vacuum leaks without finding any and had the battery checked when the code scan was done in Dec. I haven't tried sprying carb cleaner over the intake manifold but will today. At this point I pray there is a leak in the manifold just to put an end to this search that's been going on since Nov. 1 2013. This car has been down for so long that I've thought about sending it to the crushers but it has good compression and mileage is about 150K with a good auto transmission and working heat and A/C. I feel like I'm on Mars mission??
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Are you using AC Delco plugs?
 
Did you check the fuel pressure when melgs5 mentioned it. My father had a long list of codes from from his 99 chevy truck. His fuel pressure had dropped below required levels and it caused the same symptoms you have. He had a weak fuel pump. Sometimes one small problem can trigger multiple codes.
 
I do have Delco plugs. Did code scan today and got PO303,PO172,PO107. Scan checked after running showed misfire switching al over. I was rechecking compression and sparkplugs today with a friend, and he pulled #1 while it was idleing and thought it didn't make much difference in the running and that the spark seemed weak. He pulled #4 and it killed the engine and the spark was stronger. I explained that I had changed the #1#4 coil pack and he started checking fire order for misplacement. He tried pulling #2 and it also didn't make much difference and had weak spark while #3 pulled made the engine kill and had a stronger spark? Then he tried putting #1 wire on #4 and viseversa and we started it to find the engine ran the same and we swapped #2 and 3 and it still ran the same?? We can't find anything in the books saying this would work this way and we could only guess that the engine must spark twice in the 4 cycles for emissions because we'd never seen this happen this way?? He suggested I change the ignition module and see if that increases the low spark? We did put all the wires back to the correct firing order before stopping. When the wires were switched the low spark was swapped and now pulling #1 or #2 wires would make it kill while #3 and #4 wires pulled seporatly didn't kill but only slight effect was made on the idle. Does this sound possible to you about switching the wires and having the engine idle even though?
 
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