07 Z18XER EFI Issues

[Slotter]

Hi guys, i'm having a issue with my car, when cruising on a expressway, which I do every second day, when I go to accelerate from app 3000rpm the car has a distinct misfire which is not being detected by the ECU as I get no error code, I changed the coil pack & plugs out of principal cleaned the MAF & Throttle body checked for vacuum leaks etc, problem still there, just wondering if someone out there has come across this problem or if there is a list somewhere of what the scan tool readings should be on a healthy car. It is a 07 CDX Z18XER WITH 75,000 Ks. Here's hoping, Cheers Slotter.

[Slotter]

Anyone a idea or a link ???

[guy 27]

I'd be looking at data from ecu and see exactly what is causing it.

Does it only happen at high speed or at low speeds at same rpm?

[Slotter]

It only happens at high speed, had a scan tool hooked up last night but could not see anything erratic that is causing it, what I need are readings of what it should be so that I can compare, I am thinking front O2 sensor but $480 genuine I want to be sure first

[Slotter]

Last night I had Tech 2 hooked up to see if that could diagnose the problem, on the drive test, the car still had a distinct miss however, still no abnormality detected by the tool, the mechanic sitting next to me during the test was just as baffled wondering which part to throw at it next, heeeeeeelp.

[delemonte]

Is it actually high speed related or is it possible that 'high speed' simply means you're in a higher gear and therefore the engine is under more load and thus more likely to misfire? Just a thought...

Does it misfire when you suddenly load up the engine with ~3/4 throttle at a low rpm in 3rd, 4th, or 5th gear?

[gravy258]

try taking out the VVT solenoid screens and cleaning them out, i did it on mine years ago.

https://www.vectra-c.com/forum/showthread.php?196844-Z18XER-vvt

[Slotter]

Ok after chasing anything and everything, coil pack, maf, vvt screens o2 sensors etc etc it actually turned out to be the inlet side vvt sensor which had a intermittent fault, not so apparent during the colder months but as soon as the warmer months arrived so did the fault finally triggering a code

[stevens]

hi, what is VVT solenoid screens ,and inlet side vvt sensor. mine does it a bit now and then..

[Slotter]

see link https://www.vectra-c.com/forum/showt...844-Z18XER-vvt

[stevens]

see link https://www.vectra-c.com/forum/showt...844-Z18XER-vvt


just takes me to vectra forums. doesnt show anything

[Slotter]

Hopefully you solved your issue, that redirect showed the possibilities of your issue.