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Chukkieegg

Misfire/hesitation

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OK driving home tonight engine check light came on while in slow traffic. 

Tickover was lumpy got home scanned and pointed to emmisions error cleared codes and restarted

Tickover all over place went to get takeaway for kids engine light came back on would stay on for 30 seconds then would flash for 20 seconds then would stay on this was like a cycle

Back home plugged scanner back in and it was showing misfire on cylinder 4, 5,6 and both 02 sensors with an error it's a 2.5 so only 2 02sensors new coil packs and plugs were fitted about 2 months ago and had new o2 sensor and cat on left hand bank (uk car) 

Any ideas what else would cause errors above? 

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Possibly the MAF. Disconnect the electrical plug from the MAF and run the car. If the symptoms improve or disappear it points to a MAF fault.

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Thanks will give it a try tomorrow

Also once past idle ie 2000 revs or higher runs fine

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This happened to me yesterday, see my post, CPS reckons it’s the variocam actuator, which is an expensive fix I’m afraid.

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Hi Baron yes read you're post but I think the fault is slightly different will try unplugging maf and see if there's improvement but yes could be the actuator will follow you're post to see the update and fix

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OK just started up and ran it on Tickover I have noticed over last few days that's to get in below 1000 revs after initial startup up you have to blip throttle to about 1200 rpm for it to drop to 900

Sat on Tickover for a few mins no check light and Tickover steady at about 900 always moved slightly up and down since I had it not taken for a drive yet but will unplug maf and see if there's any improvement

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OK cleared codes unplugged maf and it seem to run better revs we're higher but error codes were now maf related and check light came on

Cleared codes plugged maf back in don't get any maf errors but get

Error 18 (icarsoft scanner) o2 sensor post cat cylinder 4,5 and 6

Then error code 68 cylinder 6 misfire damage to catalytic converter I get 2 other codes which are same asbove but state cylinder 5 and cylinder 4

So do I try a new maf or am I in same boat as Baron and looking at vvt solenoid? 

 

 

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3 hours ago, Chukkieegg said:

OK cleared codes unplugged maf and it seem to run better revs we're higher but error codes were now maf related and check light came on

Cleared codes plugged maf back in don't get any maf errors but get

Error 18 (icarsoft scanner) o2 sensor post cat cylinder 4,5 and 6

Then error code 68 cylinder 6 misfire damage to catalytic converter I get 2 other codes which are same asbove but state cylinder 5 and cylinder 4

So do I try a new maf or am I in same boat as Baron and looking at vvt solenoid? 

 

 

The error code sounds wrong for a 2.5 as I think the O2 sensor is pre-cat, with post cat sensors only added on later cars. What brand of O2 sensor was fitted, some cheap ones can fail quickly. I'd checkmthe coil pack connectors to make sure they're properly seated as when I changed mine a similar fault developed a few weeks later which was solved by just pushing the connector home properly.

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OK plugged in the cheap scanner we use on wife cars engine check light came on within seconds of engine start

Anyway got code P0300, P0304, P0305. And P0306 all pointing to misfires cylinders 4,5 and 6 

O2 sensor was a bosch one I checked the coil pack connections and they seemed tight but will recheck tomorrow

Car runs fine over 1500 rpm but its smells pretty rich so wondering if its the maf or if timing has slipped seems other have had timing slips the other thing is could it be a faulty aos? 

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3 hours ago, Chukkieegg said:

OK plugged in the cheap scanner we use on wife cars engine check light came on within seconds of engine start

Anyway got code P0300, P0304, P0305. And P0306 all pointing to misfires cylinders 4,5 and 6 

O2 sensor was a bosch one I checked the coil pack connections and they seemed tight but will recheck tomorrow

Car runs fine over 1500 rpm but its smells pretty rich so wondering if its the maf or if timing has slipped seems other have had timing slips the other thing is could it be a faulty aos? 

Sorry to say, but all the same issues as I’m having, I will know for sure when CPS look at it on Friday, but I think it’s pointing to the variocam.

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Yes Baron

I am thinking the same going to try with cheap scanner and maf disconnected what errors it throws as it defo ran better with maf disconnected and if it only throws maf errors with it disconnected then I will buy a maf but I am prepared for a vvt solenoid

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OK doing research I have a quick question does a 98 2.5 have varicam?  Or just the timing solenoid on each bank? 

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It has a variocam 

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So in theory it can slip did I read on you're post Baron that it can be reset just wondering if it worth getting Valve timing checked? 

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17 minutes ago, Chukkieegg said:

So in theory it can slip did I read on you're post Baron that it can be reset just wondering if it worth getting Valve timing checked? 

Yes it can slip and that could be the problem, it could also mean broken teeth, which will show in the oil change next time.

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OK thanks Baron

I have just unplugged maf and go for a short drive and see what the cheap scanner pickups I know it will throw maf errors just interested if it will stick pick up the misfire errors and will post the results it will only be at low revs and not opened up

 

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OK with maf disconnected car runs loads better but chucked scanner on and still getting the misfire errors on cylinders 4,5 and 6 so I think it's most likely same issue as Baron also noticed at idle the whole car vibrates guessing as it's running lumpy but after 1500 rpm is fine and pulls well

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57 minutes ago, Chukkieegg said:

OK with maf disconnected car runs loads better but chucked scanner on and still getting the misfire errors on cylinders 4,5 and 6 so I think it's most likely same issue as Baron also noticed at idle the whole car vibrates guessing as it's running lumpy but after 1500 rpm is fine and pulls well

Identical symptoms unfortunately.

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4 minutes ago, the baron said:

Identical symptoms unfortunately.

Baron just out of curiosity what mileage has you're boxster done 

Mine is a 98 2.5 with 131,000 on the clock bought about 6 months ago with 127 on the ckock

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19 minutes ago, Chukkieegg said:

Baron just out of curiosity what mileage has you're boxster done 

Mine is a 98 2.5 with 131,000 on the clock bought about 6 months ago with 127 on the ckock

204k trouble free, no ims issues, same engine gearbox and clutch, suspension completely swapped out, loads of ancillaries such as water pumps, coil packs oil changed every 3mths etc, thousands spent, its a well looked after car.

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Funny that you get MAF codes. 
 

I only connect mine for MOTs and I never pull a code when it’s disconnected. 
 

I've have Random misfire codes when changing from 95 to 98 Ron and back. 
 

have you recently filled up with a different fuel?

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Normally shell mostly v power and same petrol station very occasionally esso 

But car is defo lumpy was sitting in traffic when it's started playing up on Friday night  dual carrigaway upto a roundabout was down to 1 Lane 

With maf plugged back in engine light comes on in a few seconds after switch on 

Pretty sure it's going to be the vvt solenoid like Baron's issue

 

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OK can I ask which side are cylinders 4,5,6 on 

I have a manifold starting to crack which is on the left hand side and wondering if the misfire issues might be connected

If that is 4,5,6 

Not ruling out the vvt solenoid just looking at all options

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OK going to add this to the equation 

Cleared codes at dinner had driven it to work as its my daily and am driving it gently anyway drove home its a 8mile drive each way dual carriageway and 60mph engine light stayed off until I was less than a mile from home no lumpy running on tick over at all 

Car smells hot at backend could aos starting to fail cause the issues I am having and error codes? 

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29 minutes ago, Chukkieegg said:

OK going to add this to the equation 

Cleared codes at dinner had driven it to work as its my daily and am driving it gently anyway drove home its a 8mile drive each way dual carriageway and 60mph engine light stayed off until I was less than a mile from home no lumpy running on tick over at all 

Car smells hot at backend could aos starting to fail cause the issues I am having and error codes? 

Is there soot over the exhaust and on the back of the car just above exhaust?

I don’t think its that, as you would probably be getting plooms of smoke upon acceleration and feel a loss of power too. There’s alway hoping.

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