J30 2k hesitation

[cayvman]

I have a 1994 j30 with 155K miles. I've had the complete service done recently. What's happening is that at around 2K rpm, there will be a hesitation and acceleration to around 3k and then back to 2k. Typically around 40-60 mph. I had the plugs changed over the weekend thinking that might be the problem. Still there. Mechanic put it on the scanner and couldn't find anything.Any ideas?

[driverdriver]

I don't quite follow......are you talking about the RPM on the tachometer. If so, do a search with my ID (driverdriver) and transmission. You'll come across a wealth of information. It kind of sounds like you may need a transmission revolution sensor. Its hard to diagnose. You basically have to drive around with the scan tool attached to get the code.

I would also recommend that you invest in a transmission cooler. The J's transmission is known to fail in warmer climates.

[cayvman]

Thanks. Called Bill at T.O. Infiniti. He gave me some good suggestions. Will run them past my mechanic. Also, may even take it to the local dealer and give them a shot a diagnosing the problem. It's definitely not slippage, which is a good thing. Coud be the rev sensor, or throttle control sensor.

[VimyJ]

I have a 1994 j30 with 155K miles. I've had the complete service done recently. What's happening is that at around 2K rpm, there will be a hesitation and acceleration to around 3k and then back to 2k. Typically around 40-60 mph. I had the plugs changed over the weekend thinking that might be the problem. Still there. Mechanic put it on the scanner and couldn't find anything.Any ideas?

You used OEM spark plugs, correct?

[cayvman]

ngk platinum. After closer analysis of what is occurring, it appears to be something related to the transmission. The car is intermittently downshifting and then shifting back up while driving in fourth (D), typically between 40-60 mph and 2k rpm. The next step is to hook up the scanner and run diagnostics on the transmission. I did a non-scanner diagnostic (per service manual) yesterday and it turned up negative.

[maxnix]

Tell us about your transmission fluid exchanges, pan drop and clean, followed by a filter replacement before reassembly.

Do define precisely "complete service." What was really done?

[cayvman]

Transmission flush, only.Complete service: timing belt, water pump, plugs and whatever else is called for the at ~100K.

[cayvman]

Finally caved. Took my car to Infiniti dealer in Santa Monica, as advised to do by Bill (trans expert at Infiniti in Toronto). Despite my trepidation and cost fear, they discovered the problem: Turbine sensor. They sold me on having the air intake de-carbonized, said that the build-up contributed to the problem. I doubted it but didn't want to give them an excuse for the sensor replacement not fixing the problem. So, ~$600 later. Seems okay. Just got it back yesterday, so haven't had enough time and miles to convince me that the problem is fixed. Born Skeptic. But thus far, symptoms have disappeared.

[maxnix]

The dealer is correct that both probably contributed to your symptoms. Did they tell you what else needed to be addressed?

[cayvman]

For this particular problem, no. However, they said I needed a new battery, which I declined since I could do that myself for a lot less than they wanted. Lo and behold when I picked up my car and was preparing to pay for the bill, I noticed a $100 charge for a battery. Spoke to the service advisor, reminded him that I had declined that repair item, he agreed and they took the charge of my bill, but left me with a new battery. Bank error in my favor.They also told me there was a cracked boot on my rear struts, cracked boot on the rack and pinion, a leaking right strut (which I just replaced).

[cayvman]

Update. Had to have the temp sensor replaced. Even though the turbine sensor corrected 90% of the shifting problem, there was still some odd stuff going on. Took it back to the dealer, tech almost gave up, then decided to let the car warm up before testing it. Voila!!! Temp sensor was bad, too. So far, everything seems perfect.

[bvanfossen]

you said the sensor help on 90%. what was the problem on the other 10 percent? a hesitation? i have one around 2k rpm's and in low rpm acceleration. does this sound like the problems you were having?i have a '93 j30 w/ 103k miles