2002 I35 - Car intermittently won't shift out of 1st/2nd gear

[brianmcw09]

I have a 2002 I35 that I am having some problems with. It appears that the car intermittently will not shift out of 1st or 2nd gear. Sometimes, this will happen after I have been sitting at a light or pulling out of a drive thru, sometimes the car will downshift to 1st or 2nd when I am drving down the road. I tend to notice that the A/T light flashes several times on some of the trips that the car has the problem. Car has 136K miles.

Here is what I have had done so far at the local Firestone ($800 worth of work so far):1. Brought the car in to have the problem diagnosed. Codes come up for the speed sensor and thermostat malfunction (stuck open). They reset the codes and I drove it home. Problems started happening again.2. Transmission service and filter change - They did not do a flush, as they said that it could cause some problems. However, they did replace the filter and whatever transmission fluid was lost doing this. Said that there were no metal shavings in the pan and that it should take care of it. Drove it away, 1/2 hour later problem started occuring again.3. Ran additional diagnostics and said that my throttle position sensor was malfunctioning. Had them replace the throttle body and they said everything was ok. Seemed to run rough afterwards that day, so they said to bring it back to do a relearn/retrain. The next day before I brought it back problems started happening again. They said it did not appear to be the transmission was not slipping so probably not a transmission issue.4. They ran yet even more diagnostics, and found a misfire code. Replaced a coil pack and did the relearn/retrain and all seemed to work fine for a few days.5. Now for the past couple weeks it has again been failing to shift intermittently. I have found that stopping, turning the car off and back on allows it to work properly and I can get where I need to.

Any suggestions or ideas? I know it may be time to take it to the dealership to have them look at it, just trying to avoid it, and trying to save some money since money is tight. Still need to have the spark plugs changed, back brakes done, thermostat changed, motor mount changed, suspension needs work, and my right wheel bearing needs to be changed.

Let me know what your thoughts are.

[loystock]

Welcome to NICO.

I'm sorry about the nagging problem you are having. Firestone should have fixed the speed sensor and thermostat problem instead of just resetting the ECU/CEL. An open thermostat makes the engine run 'cold' (as seen by the coolant temp sensor) which affect shift points and air-fuel mixture (rich), etc. In addition a cold engine may cause oil to gum up in the galleries.

The TB replacement may not be necessary. The thermostat, if stuck open must be replaced. Your best bet is to have a free scan from Autozone and get a printout of the fault codes so we can have a better idea as to what is really wrong with your car.

At 136K miles, your transmission fluid should have been flushed multiple times already. For longer transmission life, ATF should be flushed every 24-30K miles, and I suggest that you have one. However, most shops will refuse to do a flush if a car has more than 85K miles and there is no proof of previous flush due to liability issue. A BG Flush machine is highly recommended. Never use a pneumatic flusher.

The spark plugs are good for up to 105K miles but some owners have them replaced at 60K or 90K miles. If you still have original plugs, then they are way overdue.

Looks like a lot maintenance tasks have been deferred in your car, based on the problems you are having.

[brianmcw09]

Codes are P0720 and P1574. I am wondering if Firestone took me for a ride on the repairs (and if so if I can do anything about it).

I am thinking the revolution sensor (since it has not been changed yet) needs to be replaced. What are your thoughts?

[brianmcw09]

Replaced the revolution sensor, and the problem is not occuring (for now). Irritating that I spent that much to get it repaired and I repaired it myself for $177. Lesson learned I guess.

In terms of the remaining repairs I have to do, what order should I be looking to do them in? Money is tight, so I will be lucky to be able to do one per month.

What still needs to be done:1. Thermostat2. Front Engine Mount (probably have a shop do this?)3. Right Wheel Bearing4. Rear brakes (easy enough to do myself, and probably not too expensive)5. Suspension - auto shop where I got my tires said that my shocks/struts were worn out6. Spark plugs - yes they are still the original, yes I know bad me (Should I have this done at a shop considering how difficult they are to get to?)

Looking forward to your input.

[loystock]

That's how I felt about Firestone based on your description.

Below is a link to the 02 I35 FSM (Factory Service Manual). to help you in the DIY of your car issues. Also, please refer to the Maxima?I30/I35 FAQ 'sticky' (top of the forum) in this forum as it contain a wealth of info on "How Tos."

http://www.nicoclub.com/FSM/i35/2002/

Depending on the condition of the rear brakes (safety item), if they are worn out (close to 2mm limit) they must be the top priority. You need a brake piston adapter (@ $10 from Autozone) to push the brake piston in after replacing the pads. Do not use a C-clamp as it could damage the caliper assembly. I have posted a procedure sometime ago linked below

zerothread?id=452959

For the other problems, it should be - thermostat and wheel bearing; spark plugs; front engine mount; suspension; and ATF flush. For OEM parts, NICO sponsor, Ios (Infiniti of Scottsdale) is the best and offers 25% off MSRP - infinitipartsUSA.com a.k.a. 'everythinginfiniti.com.' Here's a link for the spark plugs:

http://www.infinitipartsusa.co...gid=0

Thermostat and plug replacement and ATF flush (doing multiple drain and refill) you should be able to do on your own. The rear plug, close to the throttle may be a bit difficult but it can be done. Engine mount is doable depending on available tools to you. The bearing and suspension are best left to mechanics if you haven't done it before. Suspension job involves risk, especially with the springs (requires spring compressor). There is a 'How To info in the 'sticky.' There are numerous YouTube videos about working with suspension, if you are interested.

A lot of procedures are within the forum, just use the SEARCH button. Let me know if you need additional info.

[brianmcw09]

Thank you very much for your assistance. I will start taking care of these items.

With the brake replacement, do I need to bleed the system or can I just push the piston back in?

[loystock]

If the brake fluid is at least 2 years old or the color is other than 'champagne', then better bleed the brake, starting from the furthest brake assembly towards the one close to the reservoir. This is usually a 2-man job. However, you can buy a bleeder kit (w/ check valve) from a car parts store so it becomes a 1-man operation. Brake fluid is hygroscopic (absorbs moisture) and presence of water in the system will degrade the brake fluid (reduces boiling point) causing brake fade (or failure in an emergency).

Again, for the rear brake piston, you need an adapter to TURN it in. You cannot push it in. The front brake piston you can push in with a C-clamp, not the rear.

[PattyL]

@brianmcw09 i know this thread is now 2 years old, but after replacing the revolution sensor, to this day has the issue come back? my max hasnt been shifting passed 2nd