Fuel system cleaning

[RQ]

I have run fuel system cleaner through the gas at 1/2 tank and the J is still not running well...stalling but not cutting off, loss of power, stumbling.
The local Jiffy Lube type place injects Seafoam into the vacuum system to burn off the carbon but it fouls the plugs and you have to then replace them. I've done this on my truck before and it does clean out the carbon very well.
The Infiniti dealer does a fuel rail/system cleaning at $149.00.
What have ya'll done for this same problem?

Edit: 1997 J30

[yodawill2000]

Have you checked for a Knock sensor code ?
It wont light the "Check engine" light.
Cleaning the Maf and it's connector may also help.
Running Premium fuel ?

[driverdriver]

Is your car idling rough?

Are you sure your injectors are all running? Have you ohmed tested them (they should be in the 10-14 ohm range-anything above or below signals injector failure)?

Injector failure is common as the car ages.

[Infinitiguy19]

I have run fuel system cleaner through the gas at 1/2 tank and the J is still not running well...stalling but not cutting off, loss of power, stumbling.
The local Jiffy Lube type place injects Seafoam into the vacuum system to burn off the carbon but it fouls the plugs and you have to then replace them. I've done this on my truck before and it does clean out the carbon very well.

I used to use Seafoam and notice very little improvement. But its not worth the risk because if you pour too much in at once you risk hydro locking the engine. Now Jiffy Lube can't do a oil change right you expect them to handle such a difficult task? Put it this way like I said to the guy doing the inspection on my car "I wouldn't bring a Ford to Jiffy Lube" or other crappy shops (Joe's Bar and Transmission-Q45Tech). There just happened to be a guy who owned a Ford right behind me which I didn't notice.

Your better off taking off the intake and cleaning it by hand and tools because noting will clean it better if its really dirty.

The dealer want $150 for a BG fuel injector flush and a half a** intake clean up?!?!?! Thats outrageous but then again were in a recession.

[lino]

Like the others have said, have you check your MAF, fuel injectors, and knock sensors?

[jdurrty]

I had almost this exact same problem about a year ago. My car would start up rough then run great for a while and then out of no where while sitting at a red light, it would start to stumble and eventually die. For me it was a bad MAF sensor and the only way I figured it out was when one of my friends thought it would be funny to unplug my MAF sensor, but it ran exactly the same way it did plugged in. Even a rebuilt one from AutoZone still cost over $200, but I havent had a problem since. And I dont know how many miles you have on yours, but you might want to throw a new fuel filter in too, it helped mine out more than I thought. Either way good luck!

[RQ]

Have you checked for a Knock sensor code ?
It wont light the "Check engine" light.
Cleaning the Maf and it's connector may also help.
Running Premium fuel ?

Got to run it by and have the codes checked.

[RQ]

Is your car idling rough?

Are you sure your injectors are all running? Have you ohmed tested them (they should be in the 10-14 ohm range-anything above or below signals injector failure)?

Injector failure is common as the car ages.

I have not ohm tested them, will do so...

[RQ]

Thanks for the help, I will check all these out and report back...
RQ

[GerryO]

I have run fuel system cleaner through the gas at 1/2 tank and the J is still not running well...stalling but not cutting off, loss of power, stumbling.
The local Jiffy Lube type place injects Seafoam into the vacuum system to burn off the carbon but it fouls the plugs and you have to then replace them. I've done this on my truck before and it does clean out the carbon very well.
The Infiniti dealer does a fuel rail/system cleaning at $149.00.
What have ya'll done for this same problem?

Edit: 1997 J30

Don't like thinking about the multiple routes that cleaning liquids injected into the vacuum system can take finding their way out of a running engine, and doubt their effectiveness in comparison to a good old fashioned disassembly and manual cleaning.

If you run good gas and have a fuel filter in place, next to nothing should end up in the fuel rail and injectors will probably fail electrically long before they'll clog.

Once hurriedly started my J30 up for the first time after installing a new water pump, timing belt, oil seals, etc with the MAF connected, but with the ducting assembly not connected to the throttle bodies. It wasn't long before the engine sputtered and died. Made my wife happy for a while, as she can be jealous of the car. No air movement past the MAF communicated to the ECM = no need for gas or spark either. Vacuum leak, failed injector, dirty IAC/AAC/Air Regulator or MAF?

[RQ]

Trip to Autozone and it read that the knock sensor is bad. I have no manual. Where is this thing? Is there a thread with pics?
Thanks