Motor Experts - Can you diagnose this issue please?

sho_me_da_money

Hi guys, I registered a thread last week regarding this issue but I was explaining the symptoms via my brothers experience as I was on holiday. Im back now and can explain the problem first hand. The car has been running smooth for the most part but on random occasions the car starts jerking forward, slowing down. I'll try to explaing the best I can. We were doing 30mph in 4th gear when all of sudden, I felt like the car was slowing down (similar to when it starts coming to a halt when you run out of petty). I dropped into 3rd and the car doing the same - jerking forward, pulling back (slowing), jerking forward and pulling back (slowing) - both feet were off clutch and accelerator. Same thing happened when dropping into 2nd gear. I tried to punch down the accelerator (all the way in 2nd, 3rd or 4th) and the speed would not increase - just same burst forward, slow-down motion. I dropped into first and and felt the car get a grip - it was still doing the same jerk/pull back motion only this time it would accelerate if my foot was down. I didnt have enough road to leave it going - so theres no way of knowing if it would have stalled if I left it. I pulled over, turned off the car for about 30 secs and restarted - all fine. Im on the 2nd day and its still fine. My brother told me when he had the issue last week, he turned the car off for 10 secs, back on and everything was fine for a week before it randomly occurred again. A service is due but can any of you kind experts offer an opinion as to what is the root cause to this? The tires I replaced about 3 months ago (Grade 1 - all 4 of them). In the service I will be changing the oil filter, oil, air filter, brake pads.

C_Mababejive

Are any of the dreaded warning lights coming on on the dash?? what make/model car?

sho_me_da_money

The car is a Nissan Micra S - 55 plate. The only warning light on the dash is the Nissan spanner (that has been lit since the day we got the motor about 8 months ago). The manual describes this warning light as a problem with the Nissan Security Built in thing (lol)

NickWarren_2

I thought that the light in question was actually the engine management warning light? (Could of course be wrong)

If this is actually the engine management warning, You may need to get it read by a diagnostics machine to see if any error codes are thrown up. If you do need to then make sure you find a good independent as opposed to a main dealer.

Jem8472

The pulling back thing sounds a bit like when my coil pack when on my car. It causes it to misfire so losing power. Does the car sound like its misfiring when you get the pulling back?

kaya

fuel blockage or coil pack, its impossible to diagnose over the internet but as its intermittent i would go with the fuel system first, the coilpack itself would either fail or work, could be the supply to the coilpack though-time to change the fuelfilter methinks

sho_me_da_money

Ermm....mis-firing?????

Forgive me but I don't understand what that means. All I can explain is that we were travelling at normal speed when all of a sudden it felt like someone stepped on the brake and the car started slowing down. Once it slowed to a certain speed it just keep rolling and jerkiing forward. When I say jerking forward - imagine ur driving at 30, u take the foot off the accelerator and then u push down and let go immediately and keep repeating the action - you get like a short burst and then an immediate pull back feel. It wouldn't give me any control in 2nd, 3rd or 4th but did in 1st.

Turning off and on for 10 seconds sorted it.

The red light I spoke of above is something to do with Nissan Anti Theft system.

sho_me_da_money

kaya wrote: »

fuel blockage or coil pack, its impossible to diagnose over the internet but as its intermittent i would go with the fuel system first, the coilpack itself would either fail or work, could be the supply to the coilpack though-time to change the fuelfilter methinks

Hi mate

Thanks for this but I'm a little confused as to what order I should try and resolve this? Based on your comments, should I do it in the following order;

1. Replace fuel filter
2. Failing that, replace the coil pack
3. Failing that, investigate the supply to the coil pack

I just want to avoid getting blabbed makka and sharked.

Thanks mate!

cyclonebri1

Sorry and no disrespect, but, and a big but. take it to a garage. You do not appear to know enough about mechanics to resolve this.

maninthestreet

sho_me_da_money wrote: »

Ermm....mis-firing?????

Forgive me but I don't understand what that means. All I can explain is that we were travelling at normal speed when all of a sudden it felt like someone stepped on the brake and the car started slowing down. Once it slowed to a certain speed it just keep rolling and jerkiing forward. When I say jerking forward - imagine ur driving at 30, u take the foot off the accelerator and then u push down and let go immediately and keep repeating the action - you get like a short burst and then an immediate pull back feel. It wouldn't give me any control in 2nd, 3rd or 4th but did in 1st.

Turning off and on for 10 seconds sorted it.

The red light I spoke of above is something to do with Nissan Anti Theft system.

Misfiring - not firing on all cylinders.

jeannieblue

Bad fuel.
Coil pack.
Injector/s
Map sensor.
Air flow meter.

Bad driving skills........

Could be any of the above or none of the above. Recommend you get it to a garage for diagnosis.