Daewoo Nubira User Manual page 570

Involves a momentary lack of response as the
accelerator is pushed down. This can occur at any
vehicle speed. It is usually the most severe when first
trying to make the vehicle move, as from a stop.
Hesitation, sag, or stumble may cause the engine to
Step
1 Were the Important Preliminary Checks performed?
2
1. Check the fuel system pressure. If the pres-
sure is not within the value specified, service
the fuel system as needed.
2. Inspect the Throttle Position (TP) sensor for
binding or sticking. The TP sensor voltage
should increase at a steady rate as the throttle
is moved toward Wide Open Throttle (WOT).
Is the problem found?
3 Repair or replace any components as needed.
Is the repair complete?
4
1. Check the Manifold Absolute Pressure (MAP)
sensor response and accuracy.
2. Inspect the fuel for water contamination.
3. Check the Evaporative (EVAP) Emission canis-
ter purge system for proper operation.
Is the problem found?
5 Repair or replace any components as needed.
Is the repair complete?
6
1. Disconnect all of the fuel injector harness con-
nectors.
2. Connect an injector test light between the har-
ness terminals of each fuel injector.
3. Note the test light while cranking the engine.
Does the test light blink on all connectors?
7
1. Repair or replace the faulty fuel injector drive
harness, the connector, or the connector termi-
nal.
2. If the connections and the harnesses are good,
replace the powertrain control module
PCM)/engine control module (ECM) for an in-
ternal open in the fuel injector driver circuit.
Is the repair complete?
8 Measure the resistance of each fuel injector. The re-
sistance will increase slightly at higher tempera-
tures.
Is the fuel injector resistance within the value speci-
fied?
9 Replace any of the fuel injectors with a resistance
that is out of specifications.
Is the repair complete?
10 Perform an injector balance test.
Is the problem found?
DAEWOO V–121 BL4
HESITATION, SAG, STUMBLE
Action
ENGINE CONTROLS 1F – 367
stall if severe enough.
Important : Before diagnosing this condition, check ser-
vice bulletins for Programmable Read–Only Memory
(PROM) updates.
Value(s)
Go toStep 2
41–47 psi Go toStep 3
(284–325 kPa)
System OK
Go toStep 5
System OK
Go toStep 8
System OK
11.6–12.4 Ω
Go toStep 10
System OK
Go toStep 11
Yes No
Go to"Impor-
tant Preliminary
Checks"
Go toStep 4
Go toStep 6
Go toStep 7
Go toStep 9
Go toStep 12