yo
Do you have the report with IDLE, CRUISE, etc readings? If so, post em up here;
A leaking exhaust manifold will dump raw oxygen on the O2 sensor and can make the system attempt to go rich..in so many words;
"...If the crack siphons in cold outside air into your exhaust system, the oxygen sensor may read this as a lean condition. Consequently, it will inject extra fuel to compensate, resulting in a rich or "choke" condition. This will cause rough idling, poor fuel economy and may result in engine damage under some conditions..."
Do you have black smoke from tail pipe?
You wrote; "...No check engine light comes on
anymore..."
Do you have the Diagnostic Test Results with the Codes?
Do a Self Test anyway, this one is by our good friend, BroncoJoe19
do the KOEO = Key On Engine Off portion first
& Remember to have engine @ Normal Operating Temperature before doing the KEY ON ENGINE RUNNING (KOER) portion
Turn off all lights, radio, etc before beginning.. I get it on da road to heat it up and run through all the gears.
Some standard symptoms & reasons:
IDLE CO & HC is HIGH = Fuel pressure too high.
TPS (throttle position sensor) not adjusted correctly. (this is a common problem; we can help ya test it out)- Testing, Operation, etc., Bronco & Ford - Warm the engine up. Shut engine off, and turn ignition on. With a voltmeter on the appropriate setting, probe the TPS center wire with the (+) probe, and ground the (-) probe. Adjust the throttle plate adjustment ***** so the voltmeter’s reading is 0.9 to 1.0V DC
Source: by broncoii.org
&
Testing & Operational Description & Parameters by Ryan M (Fireguy50) at fordfuelinjection.com
LOW CRUISE CO & HC is HIGH = Timing ********,Excessive exhaust system backpressure.
TPS (throttle position sensor) bad or out of adjustment.
Sticky or plugged PCV valve. Has this been tested?
Bad O2 sensor. Check connector
Gas in crankcase.
Engine oil old or needs changing.
Leaking fuel pump diaphram.
High fuel pressure.
Charcoal cannister defective or saturated with gas (Replace it).
CRUISE (2500RPM) Dyno: 60mph @ 30hp
Exhaust smells rich?, may or may not be doggy on power = Bad MAP sensor, Bad or misadjusted TPS.
Sticky or plugged PCV valve.
Ignition timing at cruise is incorrect.
Plugged exhaust or bad catalytic converter.
High fuel pressure.
Gas in engine oil, or it needs changing
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Emissions Failures, Diagnosis Tech Tips (high CO, O, CO2, etc.) Source: by interro.com via web.archive.org
The chart below lists some of the kinds of problems that could result in abnormal gas readings.
(Legend: L = Low, H = High , M = Moderate
see site for the Chart
