This is Mrs H's 2005 Zafira A 1.6. I've already searched online, but most of what I have found is others asking for the same on Vauxhall forums but not actually getting an answer...
Symptoms:
On initial start-up, it runs fine, but soon misfires. Switching off & restarting resets it & it intially runs more smoothly before misfiring again. Once driving, the engine management light flashes intermittently, but does not do this when idling / revving the engine when stationary. When revving the engine under no load, there is initial hestiation from idle, which then clears & it picks up rpm smoothly.
I've plugged in a code reader, but there are no fault codes coming up, even when scanning for a code when the light is flashing...
(however, scanning again just now shows 3 as 'OK' and 4 as 'INC' -guessing that means inconclusive?).
As that wsn't massively useful, I tried using the pedal test which brought up the following fault code:
0300 - misfire (a lack of excrement & a fictional victorian detective spring to mind...)
Googling that has suggested that I should perhaps also be getting one of 0301 to 0304 codes, if the system is able to detect a specific cylinder which is misfiring.
On the current drive cycle scan, it comes up with the reading 'INC' for the misfire monitor, and 'N/A' for various readings which are listed as 'OK' on the drive cycle since last cleared (which would be a minimum of several years ago when I replaced a sensor on the exhaust to make the engine management light go away.
So based on what I have found so far from googling these symptoms & code, the likely suspects are as follows (in no particular order):
Fuel pump / filter
MAF sensor
Coil pack
Tomorrow morning, I'm going to check the plugs and do a compression check.
However, if the fuel pump was dodgy, would it pick up rpm so easily with no load? As it is integral with the tank, and requires that to be dropped for access, is there an easy way to check / diagnose? Some info suggested that low fuel level could be part of the problem, but adding the contents of a 5l can made no difference. Is there an easy way to check the coil pack - it's an all in one unit which bolts in place directly onto the plugs, so I can't isolate each cylinder one by one as I could with individual packs or a distributor & plug leads.
Anyhow, any advice on diagnosing what needs sorting would be very appreciated, as I really want to avoid spending cash / time on work that doesn't actually fix the problem!!
Symptoms:
On initial start-up, it runs fine, but soon misfires. Switching off & restarting resets it & it intially runs more smoothly before misfiring again. Once driving, the engine management light flashes intermittently, but does not do this when idling / revving the engine when stationary. When revving the engine under no load, there is initial hestiation from idle, which then clears & it picks up rpm smoothly.
I've plugged in a code reader, but there are no fault codes coming up, even when scanning for a code when the light is flashing...
(however, scanning again just now shows 3 as 'OK' and 4 as 'INC' -guessing that means inconclusive?).
As that wsn't massively useful, I tried using the pedal test which brought up the following fault code:
0300 - misfire (a lack of excrement & a fictional victorian detective spring to mind...)
Googling that has suggested that I should perhaps also be getting one of 0301 to 0304 codes, if the system is able to detect a specific cylinder which is misfiring.
On the current drive cycle scan, it comes up with the reading 'INC' for the misfire monitor, and 'N/A' for various readings which are listed as 'OK' on the drive cycle since last cleared (which would be a minimum of several years ago when I replaced a sensor on the exhaust to make the engine management light go away.
So based on what I have found so far from googling these symptoms & code, the likely suspects are as follows (in no particular order):
Fuel pump / filter
MAF sensor
Coil pack
Tomorrow morning, I'm going to check the plugs and do a compression check.
However, if the fuel pump was dodgy, would it pick up rpm so easily with no load? As it is integral with the tank, and requires that to be dropped for access, is there an easy way to check / diagnose? Some info suggested that low fuel level could be part of the problem, but adding the contents of a 5l can made no difference. Is there an easy way to check the coil pack - it's an all in one unit which bolts in place directly onto the plugs, so I can't isolate each cylinder one by one as I could with individual packs or a distributor & plug leads.
Anyhow, any advice on diagnosing what needs sorting would be very appreciated, as I really want to avoid spending cash / time on work that doesn't actually fix the problem!!