Need help on 97 Q45 missing (jolt) in gear stopped with A/C on.

[audiovisiony33]

I remember reading a post about the same problem on nico forum, but I can not find them anymore. Anyways I have 1997 Q45 and I have 155K right now. It started at 140K a week after spark plugs and fuel filter installation. I don't thinK it's related. I took it to infiniti dealer and they said it needs all new coils replaced to start it's about 2K and no gurantee on the job. It acts up less without AC running because RPM is lower. I have a feeling it has to do with some kind of a device that boost the rpm when AC, headlights, or steering are running. I've noticed it jolts right before rpm gets lowered after stopped at the light. When I am in gear it's 650 rpm no AC running. When driving in town for at least 15 min. with AC running I'm at 850 rpm in gear completely stopped. This is a moment I get down shift kick as a bonus at the same time because rpm is higher than usual. This always happened around 58K miles but Dave @ metro infiniti told be it is normal for these cars to do that. (I know it was B.S.)Anyways can any one help me with this problem befor I get rid of the car? It's been a great car and is if I can solve this problem.
Modified by audiovisiony33 at 4:47 PM 11/2/2006

[Q_SHIP]

Run a can of BG44K through it and see if it continues. I just had the same issue. Ended up being a few dirty injectors. It's worth the $20 for a try.

Does it just feel like "bumps" in the idle?

Welcome to Nico. This is the place to be if you want another 150k out of that car.

[Qproject]

fuking dealer, it's always the coil packs and no guarentee.

that's bull

[Q_SHIP]

Thats about it too. I can't beleive they do business like that. I swear 50% of the Nico members would be a better Q45 mechanic.

fuking dealer, it's always the coil packs and no guarentee.

that's bull

[audiovisiony33]

Thanks for your reply.

It's good to talk to people who are on the same page.(not like infiniti dealer at index page)You know exactly how I feel. It felt like someone bumped from the rear when it first happened to me at the stop light and there is no car behind me.What is BG44K ? Where can I get them ? I want to try your advise.

[96Qowner]

BG44k is a system cleaner. It isn't sold at consumer stores. You can find it on ebay or through the locator:

http://www.bgfindashop.com/locator/index.php

Or from one of our sponsors, Joe at 1-888-216-5328

[Solini]

He's talking about BG44k, you'll find a lot of members on here live by this stuff. You should be able to get it from your dealer, but I wouldn't suggest that as they charge upwards of $26 dollars

[maxnix]

It acts up less without AC running because RPM is lower. I have a feeling it has to do with some kind of a device that boost the rpm when AC, headlights, or steering are running. I've noticed it jolts right before rpm gets lowered after stopped at the light. When I am in gear it's 650 rpm no AC running. When driving in town for at least 15 min. with AC running I'm at 850 rpm in gear completely stopped. This is a moment I get down shift kick as a bonus at the same time because rpm is higher than usual. This always happened around 58K miles but Dave @ metro infiniti told be it is normal for these cars to do that. (I know it was B.S.)

Sounds like your IAC is mis-adjusted, among other things.

No maintenance history, but I bet intake plenum and EGR valve are not cleaned, nor the throttle body. Time to pay the piper or get your elbows dirty. Some posts concerning this here, but most in Infiniti Online Mechanic, where this one should probably be.

[Q45tech]

IAC misadjusted DUTY CYCLE is so very very very common...........because the TB gets dirty and the amount of TB AIR bypass [under the closed plate] changes.

An idiot mechanic/owner just tweeks the manual IAC bypass screw and things go to hell immediately. Trying to fix a low idle shake, etc. lean misfire, dirty spark plugs/injectors or carbon fluff on intake valves

HAVING a more than 50 rpm difference [AC on vs off] is the warning sign.

[audiovisiony33]

Where is IAC controller?When you say warning sign what can it be done to fix it?When I took the car in to the dealer they told me they reset the computer and adjusted the idle to the factory setting. (Same **** when I picked up)At idle it's about 50 rpm difference. As I drive around with AC running feels like pressure or something is building up holding about 850 rpm stopped in gear. That's the time I feel the kick (kicks forward) from the down shifting kick which bugs me alot sometimes and I turn off the AC.As far as maintainance I have done 60K service. Another fluid change @ 120K (Cooling & transmission flush) @ infiniti dealer.

[Qproject]

Wow q45tech and maxnix were right on the money.

Where is IAC controller?When you say warning sign what can it be done to fix it?When I took the car in to the dealer they told me they reset the computer and adjusted the idle to the factory setting. (Same **** when I picked up)At idle it's about 50 rpm difference. As I drive around with AC running feels like pressure or something is building up holding about 850 rpm stopped in gear. That's the time I feel the kick (kicks forward) from the down shifting kick which bugs me alot sometimes and I turn off the AC.As far as maintainance I have done 60K service. Another fluid change @ 120K (Cooling & transmission flush) @ infiniti dealer.

[maxnix]

Where is IAC controller?When you say warning sign what can it be done to fix it?

As far as maintainance I have done 60K service. Another fluid change @ 120K (Cooling & transmission flush) @ infiniti dealer.

Download an FSM and the TSB. Study it.

Search for IAC and read posts by Q45tech on this board in this and Infiniti Online Mechanic Forum. At least you will get to the point where the dealers can't blow smoke up your hiney.

Bet they didn't use disteilled water to dilute the coolant. I would definitely inquire what is considered a "transmission flush" by them (you never know). Bet it didn't include a pan drop and filter replacement. If you just daid "Huh?", please spend some time readin the previous posts. A lot to learn. A lot of money to be saved.

[Q45tech]

The ecu is preprogrammed for a suitable idle rpm which it controlls by changing the duty cycle on IAC [as a last resort] and adjusting the ignition advance and fuel injector time........it assumes a 10% IAC duty cycle is normal [ac off].

2 sources of air: What flows under closed throttle and what flows around IAC adjustable bypass screw are obviously uncontrollable by ecu.

The MAF tells ecu total air flow into engine which [airflow] is split up between under throttle plate, manual IAC bypass, and IAC solenoid controlled by ecu.