coug66

po300 and p1200 ???

Po300 and p1200 codes being thrown.
the car jerks when it a accelerates.
I rest codes but could not get the VCS light to go out. The car drove a little better with the lights on. Then I had these codes above same as before and reset the VCS so no codes but car jerks while accelerating.

I had an issue with the fuel pump. Replaced and it didn't get power or work. I played with the relays and after jumping them got the car to start and run ok.
Replaced the relays but can't explain why it didn't work before?

The car also had a miss earlier while idling but I get a miss fire but not cylinder specific?

When I accelerate on an onramp or pass a car at high speed it jerks as it accelerates. Almost like bad shifting if you kept playing with the clutch on a manual transmission?
This car has ***** when it runs right but this pushing the pedal down and have it jerks as it tries to build rpms is very frustrating.

Any tips where I should look would be helpful!

Thank you,

Ian

StanVanDam

Even though you replaced the fuel pump, the fuel pump is still showing a current code, P1200, in addition to the historical code, meaning there is currently a short or open in the fuel pump relay circuit. Is it possible your fuel pump is manufactured to below OEM standards? Fuel pressure at idle measured by a gauge attached to the RH fuel delivery pipe pulsation damper should be 304-343 kPA (44-50psi), and should measure 147 kPa (21psi) or more for at least 5 minutes after engine is stopped. The resistance across fuel pump pins 4 and 5 should be 0.2 to 3.0 Ohms at 20C (68F). Also check fuel pressure regulators and injectors.

P1200 inspection procedure:
1) Remove engine ECU cover
2) Start engine
3) Measure voltage between FPR (fuel pump relay) and body ground while racing the engine. Within the first 60 seconds of engine start, the voltage should be 9-14V. After 60 seconds, voltage should be 0-3V.
4) Check fuel pump relay in the engine room #1 R/B, it is clearly marked FUEL PUMP. Ensure there is continuity between terminals 1 and 2, and between 3 and 4. If no continuity, replace the relay.
5) Apply battery voltage across terminals 1 and 2, then ensure there is no continuity between terminals 3 and 4. If there is continuity, replace the relay.

Regarding P0300, in order to memorize the DTCs of the misfires, you need to idle for at least 3.5 minutes, then run the engine at 1000rpm for at least 3 minutes, then run the engine at 2000rpm for at least 1.5 minutes, then run the engine at 3000rpm for at least 1 minute. Then turn engine off and wait at least 5 seconds. If you have misfires on specific cylinders, then you can check ignition coils and fuel injectors of the misfiring cylinders.

Check your STFT and LTFT, if any is outside +/- 20%, it may indicate a related problem.

coug66

Thank you, I will check soon when I get a chance the list.
This is the pump I bought.

Denso 950-0107 Fuel Pump
Denso I will check voltage and run tests.

coug66

I cleared the codes, the fuel pump code was from the recent fuel pump repair and playing and replacing relays and fuses.

The car has been having intermittent stumbling and hesitation accelerating. I was driving down the road and it came on again. I did the reving the motor to get a good code on the miss fire.

I then pulled the codes and it popped up P302 so I ordered a coil and will install. Cylinder 2 couldn't be an easier coil to replace so I am very happy.

I bought cheap coils in the past but unfortunately the 6 extra originals I replaced are not in my trunk when I looked.

Hopefully I will be running smoothly tommorow night.

Update

I pulled the airbox tube off and replaced the coil. Car runs great again. smooth and accelerates perfectly. amazing looking back that I didnt suspect a coil. It seems so obvious now but it was the intermittent nature of the problem. It would run OK then suddenly start to stutter, its was also covered by a failing fuel pump. SO two issues now resolved and I have my great car back again.