Engine surge during warm up.

DTC P1400: Cold Start Emission Reduction Control System

Circuit/System Description
The catalytic converter must be warmed to efficiently reduce the emissions. The cold start strategy is to reduce the amount of time it takes to warm the catalytic converter. During a cold start, the engine idle speed is elevated and spark timing is retarded to allow the catalyst to warm quickly. This diagnostic monitors the following to build an exhaust energy model:
• Engine speed
• Spark advance
• Throttle position
• Engine airflow
• Engine coolant temperature
• Engine run time
• Park/Neutral position
• Vehicle speed
The actual model is then compared to the expected exhaust energy model.


Diagnostic Aids
Any loading of the engine that lowers engine RPM, such as partial application of the clutch, A/C cycling, etc. during the first 120 seconds of the engine run time may set this DTC.
Circuit/System Verification
Allow the engine to cool.
Start and idle the engine for at least 2 minutes.
DTC P1400 should run and pass.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Inspect the air intake system for the following:
• Modified, damaged, or restricted
• Dirty or deteriorating air filter element
• Crankcase ventilation system for correct operation.
• Water intrusion
• Vacuum leak and other unmetered air downstream of the MAF sensor
• Intake manifold leak
Inspect the exhaust system for the following:
• Water intrusion
• Exhaust leak
• Damaged, restricted, modified or enhanced exhaust system.
Inspect the engine mechanical for items that could alter the air flow into the combustion chamber.


Basically it's not getting enough fuel

Hi. The "Drive Cycle" isn't different for your vehicle. The ECU has to be satisfied from the information received during the road test or drive time. A true drive cycle is 24hrs. The vehicle must meet the criteria to achieve a true drive cycle. The computer will wake up and monitor all systems (Self Check) and gather information while driving at low and highway speeds. A full drive cycle would include proper engine warm up temperature, .5hr of inner city driving, .5-.75hr of highway driving and engine cool down. After the engine and transmission cool down. All the different temperature sensors should be reading the same ambient temperature. The computers shut themselves down (sleep mode). The next day you start the engine and the next drive cycle begins.

What code is it throwing ? Some codes are what are called two trip codes ! You clear the codes an start an drive the vehicle ,no check engine light . Park the vehicle over night an bam next time you start an drive the vehicle the check engine light comes back on .

??There are two types of DTC's, 1 trip DTC's and 2

trip DTC's

??A 1 trip DTC is for a condition that requires

immediate attention such as a catalyst damaging

misfire.

??A 2 Trip DTC is one that a condition must be found

during 2 consecutive trips such as an EGR fault.

??Most Monitors do not set a DTC and light the MIL

when a vehicle fails a test for the first time during a

DRIVE CYCLE. If a test is failed on a second

consecutive DRIVE CYCLE the MIL will light and a

DTC is stored in the vehicles powertrain control
module (PCM).

Always check for trouble codes when the check engine light turns on during engine running. After repairs are made, a scanner can be used to erase the codes.

It sounds like a fuel problem, so you would need to have the fuel pressure tested. This will verify the fuel pump and fuel filter are not the problem if the pressure is correct.

Idle air control motor. Clean it or replace it.

you didnt say if it was happening only during the initial warm up of the vehicle or all the time. if it is just during warm up this is not too unusual as long as the engine isnt racing. if it is just a "high idle", say arround 2,000 rpm's its normal. the idle would usually go down as the vehicle reaches operating temperature. when you put the vehicle in gear, you are actually loading the engine slightly, thats why the idle comes down then. when in park the engine has no load on it so it is free to rev a little higher at these times. if it a at a high idle constantly, then i would start looking for sticking throttle cable, binding throttle plates, ect and remedy the problem. this should not have anything to do with the dual exhaust.

DTC P1781 - Engine Torque Signal Circuit

This code is set during engine start up when the ECM & TCM do not communicate properly during initial power up. It will only illuminate the service light if the condition occurs in 2 consecutive start cycles, but the DTC will be stored in the failure records after the first cycle.

Hope helps.

Check the fuel filter,or just change it,it is more likely it is stopped up.

Based on the information that you have provided me, my attention is now centered on the ECT Sensor (Engine Coolant Temperature). This sensor provides information to the ECM to richen the fuel mixture on start up and also to lean out the mixture as the engine warms up. Very similar to the old fashioned choke in operation. A cold engine requires additional fuel to start, while a warm one does not. This matches your situation of a cold start versus a re-start and also explains why you are having to cycle the start sequence several times to fire the engine. Those cycles are finally providing enough fuel for start up.

Check with a local auto parts outlet to see about having the ECM read for a memory code related to the ECT. Most of the stores will now do this testing for free.

Let me know if this helps you out or not. Thanks.

Clean the temperature sensor wire connector.
Replace the temp sensor.
Check the condition of the sensor wire cut(s) or short onto the engine block.
Monitor the fan operation with the hood open during warm up (0-15 minutes.) It should ran after the engine coolant temp get above 195F +.