08 nissan pathfinder surging/missing

[FishingSETX]

Ok, I am at the end of my chain here!!!! My wifes 08 patfinder 4.0l `70k is missing at low throttle input. Basically a normal drive goes like this:

Cranks up great and no problem at idle.

Place in reverse and start rolling back, and still no problem until a very small amount of throttle is given then it misses/surges a few times. give it more throttle and it backs out great.

Place in drive and everything is fine. Accelerate to ~45 mph and coast for a sec. give it just a slight bit of throttle and the missing/surging comes back. more throttle cures the problem. accelerate to 70 mph and have the same problems cured by more throttle.

basically anytime you coast a sec then put your foot on the gas (very little throttle input), it surges/misses. Give it a bit more gas and it stops missing.

Took it to my local transmission shop (they do great work) and had the trans checked thinking it was a shifting problem and they said it wasnt the trans.

tried running several tanks of premium through it and even tried some injector cleaner with no luck. The problem has been getting worse and worse over the last month or 3. First thing I tried to check was the fuel filter (act just like a dirty one) but quickly found out it didnt have one Im an electrician by trade and done lots of work on my older trucks up to and including rebuilds, but I just cant seem to put the two together on these newer vehicles!!!!!!

Anyone have the same problem? Any ideas on where to start?

[Towncivilian]

You should already be running premium fuel always for best performance. The 2008 Pathfinder owner's manual recommends 91 octane minimum. The difference per fill up is only several dollars, and running premium will likely result in a noticeable performance increase. Read here for more information.

What brand of fuel injector cleaner did you run? Many of them are ineffective. Fuel system cleaners that contain poly ether amines are known to be effective cleaners and do not leave their own deposits. Chevron Techron, Redline SI-1, and Gumout Regane all contain PEA. Redline SI-1 contains the most and can be found for rather cheap on Amazon.

You are correct in the fact that 2005 and newer Pathfinders do not have external user serviceable in-line filters. The only filter is a sock-type filter on the fuel pump itself, and it is usually only changed out when the fuel pump dies. I, too, dislike this practice on newer vehicles.

Perhaps try cleaning the throttle body? Does the service engine soon light ever illuminate during the misfiring/surging? It should be blinking during a misfire.

[FishingSETX]

Don remember the injector cleaner we used and we havent seen an engine light or any other warning. Ill order the good stuff today and give it a try. I might even try cleaning the throttle body this weekend. What exactly is involved in that and how long should it take for an average person?

[Towncivilian]

Cleaning the throttle body involves removing the air intake tube, then spraying throttle body cleaner to dissolve any carbon build up which may be interfering with the operation of the throttle. See this guide - it's for a different engine, but the procedure is essentially identical.

[FishingSETX]

ok, tried cleaning the throttle body with no luck. also took a look at the MAF and it looked clean. running out of ideas QUICK!!!

[Towncivilian]

Try cleaning the MAF sensor regardless. Use some MAF cleaner, not the same stuff you used for the throttle body.

[Malo70]

Our R51 common rail diesel Nissan Pathfinder has been surging/missing as it approaches 60 km/h, when we back off the throttle and lightly accelerate then it drives well until 80km/h and then 100km/h were it repeats the same action as it did at 60km/h. Have attended 3 mechanics. No codes observed during testing despite the very obvious symptoms. Unlikely to be transmission. They suggested a long process of elimination starting with the fuel lines at great expense without necessary success.

Does anyone have similar experience and hopefully a remedy?

Mark