My car has been idling very rough. The mechanic tells me it is the fuel injector but the code in the manual refers to rich/weak mixture. would the injector cause that fault? The diagnostic was based on the fact when we diconnected one of the spark plugs there was no difference in the way the engine was idling. The plug, wire and cap were fine. The other 4 spark plugs made a significant difference. I also noticed excessive fuel consumption. If it it the injector, can I find a rebuilt or I have to buy a new one???

Thnaks

If the #1 spark plug is black and oily, could it be time for a new plug or 5? Yes, you can replace just one injector or you could try cleaning it first. Depending on the miles you have on this tune up, you may just want to get the car tuned. What if it is just a bad distributer cap or plug wire?
I don't like the fact that he pulled #1 plug wire and said injector.

Klaus
--
98 V70Rawd(101Kmi), 95 854T(85K mi), 75 164E(173K mi)

It can be the MAF sensor too (air filter box outlet...). I'll send you the troubleshooting guide.


Mike
'95 850T




2-3-2 (Adaptive HO2S Control Provides Richer Mixture At Idle)
(H02S = Heated O2 Sensor)

1) If Codes 2-1-2 or 1-1-3 are displayed, go to step 8) and
check HO2S sensor lead. If Code 2-2-1 is displayed, go to next step.

2) Disconnect Mass Airflow (MAF) sensor connector. Turn
ignition on. Connect voltmeter between MAF sensor connector terminal
No. 4 and ground. See Fig. 5. If voltmeter indicates about 2.7 volts,
go to next step. If voltmeter does not indicate about 2.7 volts, clean
MAF sensor connector and measure voltage again. If voltage is still
incorrect, repeat test using new MAF sensor. Clear codes. See
CLEARING CODES.

3) Disconnect HO2S female connector to ECU. Turn ignition on.
Connect voltmeter between connector terminal No. 2 and ground. See
Fig. 6. If about zero volts are present, check circuit between HO2S
connector terminal No. 2 and fuel injection ECU for an open circuit.
If voltmeter indicates more than 5 volts, check circuit between HO2S
connector terminal No. 2 and fuel injection ECU for a short to
voltage. If voltmeter indicates about 2 volts, go to next step.

4) Turn ignition on. Connect voltmeter between HO2S connector
terminal No. 1 and ground. If battery voltage is present,
go to next step. If battery voltage is not present, check circuit
between HO2S connector No. 1 and main relay No. 3.

5) Turn ignition off. Connect an ohmmeter between both male
pins of HO2S connector. If ohmmeter indicates about 3-13 ohms,
(depending on temperature), go to next step. If ohmmeter does not
indicate about 3-13 ohms, retest system using a new oxygen sensor.

6) Check for leakage at vacuum lines and connections. If vacuum leaks are found, repair as necessary and clear codes. If vacuum leakage is not found, go to next step.

7) Check fuel pressure. See procedures under FUEL SYSTEM in
the F - BASIC TESTING article. If fuel pressure is correct, see test
procedures under ELECTRONIC CONTROL UNIT - FUEL INJECTION in the
I - SYSTEM/COMPONENT TESTS article. If fuel pressure is incorrect,
repair as necessary. Clear codes, if present.

8) If Codes 2-1-2 or 1-1-3 were displayed in step 1), turn
ignition on. Disconnect HO2S male connector at ECU. Connect voltmeter
between connector terminals No. 1 and 2. Voltmeter should
indicate approximately .4-.5 volt. If voltage is to specification, go
to next step. If voltage is not to specification, reconnect connector
and go to step 10).

9) Reconnect HO2S connector. Start engine and run to normal
operating temperature. Connect voltmeter between HO2S connectors No. 1
and 2. Voltmeter should indicate .1-.9 volt. If voltage is
not present, repeat test using new HO2S sensor. Clear codes. If
voltage is present, fault is intermittent. Check HO2S connector for
damage or poor connection. Clear codes.

10) If voltage was not to specification in step 8), turn
ignition off. Disconnect fuel injection ECU. Connect an ohmmeter
between connector terminals No. 1 and 2. If ohmmeter indicates
infinite resistance, check Green/Black wire between connector terminal
No. 2 and ECU pin No. 22 for an open circuit. If ohmmeter does not
indicate infinite resistance, check Green/Black wire between connector
terminal No. 2 and ECU pin No. 22 for a short to ground. Clear codes.

Thanks. It turned out to be the manifold gasket leaking.