I3o power and fuel economy issue

[dskorski]

I have a 1998 Infiniti I30 with only 40K miles. Recently, there seems to be a surge and back off of the engine when climbing small grades (any gear and any speed). The effect is fairly subtle and passengers don't seem to notice. Also, the fuel economy has changed - from approximately 340 miles per tankful to only 300. There is no indication of a "check engine" light or any other problem. The car starts fine and accelerates without hesitation. The problem is most apparent when trying to maintain a steady speed while going up a slight grade.

Any help or thoughts would be most appreciated0

[maxhopper]

I would suggest a throttle body cleaning, a can of BG 44k in the gas, and having the intake and EGR passages cleaned with something like Wynn's.With only 40k on the motor, has it sat for long periods, or just driven a few miles daily?

[dskorski]

The car did sit for a few months back in the early part of last summer, but after Labor Day, the car was driven at least 30 miles per day. These symptoms only started about two months ago.

[audtatious]

Yeah, try cleaning the MAF and throttle body. Check the air filter as well and if you have not changed your plugs, this would be a good time to do it.

[dskorski]

I will try what you suggested. Where can I find BG44K? None of the parts stores here have it.

[maxhopper]

Try a dealership parts department, or try a google search. If you have a problem getting it, shoot me an e-mail...I'll get some for you.

[dskorski]

Thanks for the offer, but I found some today at one of the BG distributors. I added it to a full tank and drove about 250 miles. There seems to be some improvement, but there is still a bit of a surge on small uphill grades. Is there an easy way to check the coils? I am just about ready to start digging in and finding this problem.

[chris_randolph]

I don't know if you are having the same problem I am having, but I will tell you anyway. First, my problem is while I am going down the road and slightly accelerating or cruising, I can feel some jerking. I posted on NICO, and they suggested that I was "bogging the motor down" by having the AC on and being in overdrive. I now drive around with my overdrive turned off until I hit about 50mph. I know you said at any speed, but does it give you this problem when going 70 and up a slight hill? It is probably too low of rpm while trying to go up the hill. Turn off the overdrive until you get up around 50.