Slight Hesitation Returns
Discussion
Hi, okay so I've had a 12k service and a diagnostic check to fix the misfire, car was running great until this weekend when the slight hesitation / misfire returned. Guess its not the spark plugs as they were replaced, ordered new HT leads from Clevor Trevor as I still have the originals. Are they easy to replace, pics/procedure would be great if anyone can post.
If its not the Leads what else?
PS occurs when engine is fully upto temp and around 3000rpm
If its not the Leads what else?
PS occurs when engine is fully upto temp and around 3000rpm
TuscSam,
I am currently experiencing the same or similar symptoms...well the car is. The motor starts and idles perfectly. But when at operating temp around 3100 rpm develops a slight miss. On max acceleration that slight miss becomes very severe at different rpm’s, high 4’s right through to 6’s.
It also periodically when cruising appears to just run on say 4 or cylinders, you back off some, accelerate and it then runs perfectly.
It has just had a recent tune and road test with NTR coming back. The symptoms didn’t occur when the shop drove it. I am thinking it is either fuel or electrical.
I suspect it’s not the coil pack otherwise it would most probably break down all the time so I will go through the process of elimination and replace plugs, leads and fuel filter.
I expect the parts in the mail soon, so I will keep you informed with the progress.
Have a look at : http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
I am currently experiencing the same or similar symptoms...well the car is. The motor starts and idles perfectly. But when at operating temp around 3100 rpm develops a slight miss. On max acceleration that slight miss becomes very severe at different rpm’s, high 4’s right through to 6’s.
It also periodically when cruising appears to just run on say 4 or cylinders, you back off some, accelerate and it then runs perfectly.
It has just had a recent tune and road test with NTR coming back. The symptoms didn’t occur when the shop drove it. I am thinking it is either fuel or electrical.
I suspect it’s not the coil pack otherwise it would most probably break down all the time so I will go through the process of elimination and replace plugs, leads and fuel filter.
I expect the parts in the mail soon, so I will keep you informed with the progress.
Have a look at : http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Ok, I'll have a go at this one....
I think this is a tricky one as I reckon there can be a number of reasons these kind of symptoms occur. If you are noticing a slight hesitance at a constant throttle then it could be one or more of the throttle-pots giving spurious signals back to the ECU which in turn cause fueling errors. It could also be a sign of excessive wear in the throttle-body spindle which, again, causes spurious signals back to the ECU and/or incorrectly metered air into the throttle-bodies. If the problem is occurring around 3 to 4Krpm then the Lambda sensors might be causing an issue or possibly highlighting an issue with fueling or air-flow regulation. However, the lambda's are taken out of the closed-loop control upon hard acceleration (WOT) or over (I think) around 4Krpm.
If you notice a stuttering under acceleration, especially higher up in the rev range then that could point to the coil-pack I think. HT leads and plugs could also be at fault as could the routing of the crank-sensor wiring (check it isn't too close to the HT leads near to the bulk-head).
Checking the status of the TP's, injectors, error codes, lambda sensors etc using the diagnostics software (whilst using the SP6 software manual as a guide) can help to identify any dodgy areas that would be immediately noticeable. I wouldn't recommend making any changes with the software unless you really know what you are doing - although resetting the adaptive maps can help to settle things down again but if there is a problem then it wont be long before the adaptives max out again anyway...
Failing any of that, a trip to your preferred garage to have them take a look at it is always an option
HTH
Andy
I think this is a tricky one as I reckon there can be a number of reasons these kind of symptoms occur. If you are noticing a slight hesitance at a constant throttle then it could be one or more of the throttle-pots giving spurious signals back to the ECU which in turn cause fueling errors. It could also be a sign of excessive wear in the throttle-body spindle which, again, causes spurious signals back to the ECU and/or incorrectly metered air into the throttle-bodies. If the problem is occurring around 3 to 4Krpm then the Lambda sensors might be causing an issue or possibly highlighting an issue with fueling or air-flow regulation. However, the lambda's are taken out of the closed-loop control upon hard acceleration (WOT) or over (I think) around 4Krpm.
If you notice a stuttering under acceleration, especially higher up in the rev range then that could point to the coil-pack I think. HT leads and plugs could also be at fault as could the routing of the crank-sensor wiring (check it isn't too close to the HT leads near to the bulk-head).
Checking the status of the TP's, injectors, error codes, lambda sensors etc using the diagnostics software (whilst using the SP6 software manual as a guide) can help to identify any dodgy areas that would be immediately noticeable. I wouldn't recommend making any changes with the software unless you really know what you are doing - although resetting the adaptive maps can help to settle things down again but if there is a problem then it wont be long before the adaptives max out again anyway...
Failing any of that, a trip to your preferred garage to have them take a look at it is always an option
HTH
Andy
Thanks Guys, will have a look at the other thread and consider the options. My Local Indie did say the Lambdas seemed to be okay after looking at the Diag software but may just pop up and see them tonight to see if he can have another look and check it out. Having had the beast for 6 months now and only had a couple of trips with it fixed after my 12k service its getting irksome !!
We had a very similar problem with the Tamora. Hesitation / misfire when up to operating temperature. Sometimes it would just go away. We didn't have any EFI faults when this was happening so we looked beyond the fuelling system and pin pointed it to the coil pack. Changed that and not had a moments trouble since 
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