I'm new to this Forum. I'm from Long Island, NY. I have a '97 Q45 with 196K miles. I bought it 8 yrs ago with 76K. The only major part that has been replaced is the alternator, which was recalled and taken care of with the previous owner. I did a rather expensive tune-up at the dealer at 120K miles about 5 yrs ago. After my $1900 bill, I didn't return back. I've been doing regular maintenance at a local mechanic since. Throughout the years, all 4 O2 sensors needed replacement.

Lately, my car has been shutting off very frequently at idle, like at a red light. I replaced the fuel filter, air filter, cleaned Throttle Body, checked vacuum system and EGR. The problem of the car shutting off wasn't resolved until the MAF sensor was cleaned.

Now the car occasionally hesitates while depressing the gas pedal at any speed. It's usually more noticeable 40mph and higher. The best way to describe it is if the engine were to talk it, it would say "Ba Boom, Ba Boom." It feels like if you were in a night club with the DJ moving his hand back and forth on the record player. The car hasn't shut off or displayed a check engine light for any of theses problems, yet the check engine light bulb is working.

I was reading through the posts and one guy seemed to have a similar situation to mine. He had good coils but a bad boot. I haven't replaced my coils yet on this car because a bad coil should give a code and a check engine light, right?

I have one other minor problem. I never have a problem starting the car in the morning. Sometimes after driving the car for a while, like coming home from work, I'd stop by the gym. An hour or so later when I go to start the car, it will crank for like 5 seconds, maybe a little more before the car engages. It's been doing it for yrs. I've never replaced the starter. If this is a starter issue, why would it not reveal itself on a cold start in the morning. Did this occur to any one?

I love this car. I'd like to sustain it's life for as long as I could. Other than these problems, the car runs like it did when I first purchased it. Solid.

Any Suggestions for these symptoms would be greatly appreciated. Thanks!

On a OBD2 equipped car, such as yours, check engine lights up ONLY after the same problem is detected after 2 back to back driving conditions- unless it is a misfire, which lights the lamp on the first time happening. You need to wait til problem occurs again then immediately check for PENDING codes stored in ECU....pending codes are problems detected on the last driving cycle and will not illuminate the CEL unless same problem is detected on 2 or more back to back driving cycles,otherwise they are automatically erased from ECU.

Thanks for the info. I guess I'll wait until the problem is more pronounced before I do anything.

I thought the car shutting off at idle was solved. It's back. Actually, it probably never left. It happens in really bad stop and go traffic. So, I've been throwing the car in neutral and tapping on the gas pedal to keep the car from shutting down.

From the sounds of it I will say it's your MAF. try cleaning the sensor

I put about 500 miles on since I had my first post. It just seems like there is a lot of hesitation at 60 mph and less. I have to drive about 70-75mph to avoid hesitation. Do you think the car shutting off at idle is related to the car hesitating while driving?

Time to seek professional diagnosis and help.

I agree. I'm going to take it in to Mavis and have them flush out the system. I hope it's as minor as just a lot of crud and carbon deposits in the fuel injectors and EGR passages that need to be blown out.

Mopar wrote:From the sounds of it I will say it's your MAF. try cleaning the sensor

Have you looked at the MAF?

One of the best ways to diagnose, is to let the car idle (parked) and disconnect the MAF. If you notice little to no change, the MAF isn't doing it's job.

The mechanic that I took it to cleaned it and said that the MAF is working fine.

Check the fuel pressure, between fuel filter and fuel rail - 34 PSI with engine running and 43 PSI with engine off, Ignition ON (limited to 5 seconds). You may have to pinch the fuel line (observe fuel pressure reading) to check if you have leak in the pump area, FPR or injector(s). It could be the ignition coil but it usually give you a trouble code + CEL. A failing dirty MAF sensor may not necessarily throw a fault code. I clean the MAF sensor every 2 years, including the connector and apply dielectric grease on the connector. Using a DVM to measure MAF voltage is not good enough; an oscilloscope will do a better job.

Thanks for the advice.

First, get an OBD II scan and report fault codes. But look them up yourself first.

Next, inspect all connections, especially the MAF one.

I ended up taking it to the dealer. I was a bit worried when they told me it was going to be $250 just diagnose the problem and that they would call me with an estimate. It turns out that when they called, they said the the car is fixed and your bill is $271 ($250 + tax). The guy adjusted the Idle Air Control. I drove it 20 miles without the car shutting off or shaking.

Btw, they gave me a G37X as a loaner while they were working on my car. That thing is powerful. The car was just begging to be pushed. It was thrilling, but I was glad to have my Q back. The Q is powerful, yet calm.

The very next day the car was hesitating and stalling again. The car won't stall as long as you tap the gas pedal. So, I brought it back to the dealer. They couldn't come up with a diagnosis. They RECOMMENDED for me to REPLACE the exhaust from the Catalytic Converter through the muffler BEFORE they can give me a diagnosis.

The car has some small leaks in the exhaust. I patched up a big hole last year at Meineke. The car is quiet and there is no noticeable loss of power or gas mileage.

They don't want to deal with the car. So, when I picked up the car, I spoke to the mechanic. He said it was odd that the Check engine light was not on. These mechanics are so dependent on the CEL to diagnose the problem. The mechanic was hinting to get rid of the car by saying the exhaust may cost more to replace than what the car is worth. That was their way out of having to figure out what's wrong with the car.

The dealer should know how to fix their own cars, especially one that is 14 yrs old. I want to pay them to fix it, but they want nothing to do with it. It's unbelievable. I experienced this at Infiniti of Massapequa. They opened when Infiniti began selling cars in the US. I'm disappointed in the injustice my car received.

Not too many senior Infiniti techs left so they are unfamiliar with anything pre 2001.

Where are you located? It is not in your profile. Perhaps we can direct you somewhere more competent. No codes cited either? The idle adjustment screw is treating the symptoms but ignoring the cause.

You didn't mention maintenance history, but usually around 130K -150K these cars need a plenum job maybe down to the KS, and also coil pack replacement.

Actually, they had 4 guys look at it, 2 of which were with the company since it opened 20 something yrs ago. They are the top Infiniti for most sales in the country. I'm in Long Island, NY.

No codes or CEL light.

I don't think I had a plenum job or coil replacement unless it was done with the 120K mile tune-up that cost me $1900 at the dealer, which was about 5 yrs ago. That included spark plugs, ignition wires, transmission fluid, fuel filter, air filter and some other things. I didn't replace the timing chain either.

They said that the car is not misfiring. I thought the coils, injectors, plugs all show a code if they aren't working correctly.

I think it might be time to put this car to rest. I appreciate all the advice.

If you can get it to PA, then take it to Keith Vanmeter.

You may want to review the excellent plenum R&R post by paranoidjack.

Sounds like a case of deferred maintenance. Depends how badly you want it to run correctly again.

Not Kings? I would like to know precisely what the two senior Infiniti technicians said. I think they just gave up on it and assumed no one would want to pay dealer book rates to do what is really required.

I only spoke to one mechanic who was not one of the senior guys. There were other mechanics doing nothing, but they didn't want to be part of the conversation. It does sound like deferred maintenance. They didn't care that I'd have to spend a lot on an exhaust that I don't need. I'll look into that plenum job. Thanks.

I was so pissed off that Infiniti charged me for a diagnosis that I never received that I wrote a letter to Infiniti Consumer Affairs. I never wrote a letter to a company before. I just felled compelled to since I was cheated. The agent didn't get back to me so I ended up stopping the payment and got my money back from the credit card company at no cost to me. However, I did get rid of my car. I traded the Q in for an Avalon at a Toyota dealership and they gave me $1,800 for it. Performance wise, the Avalon is a downgrade in every aspect, but I am getting much better gas mileage.