Poor acceleration. Please help!

[pirenuri2]

Please help.I recently bought a 98 Q45 with 140K. I had no idea what I was getting into. It is definitely a wrong car for me. The car is running rich and it has acceleration problems.

Symptoms are:1- The car stalls when I try to restart if the car is warm. It starts up fine on the second try.2- Acceleration problem gets worst if the car is warm.3- Some mornings it smells like a rotten egg.

About a month ago I replaced the MAF (after market) and used two cans of BG44k. The car now runs quieter and accelerate slightly better. However it still runs rich and acceleration poorly. With full tank, I get about 210 miles (50% highway + 50% local)

I was told that bad KS can cause this types of behavior. According to infinity cust-service KS are never been replaced. I was thinking about purchasing 2KS and harness from infinitiparts.com replacing them myself using technique described in this article zerothread?id=116280. Is it a very big job to take on myself?

By any means I am not a mechanic but I consider myself handy. I simply can not afford $500 labor right now. But I just don't want to be without a car for days.

One member also suggested that it might be bad Maf connector. How do you check if the integrity of the connector? Visually connectors seems fine.

Thank you very much in advance.

[maxnix]

You inspect MAF connector very carefully to ensure integrity of connections of wire to spades to connector body.

Used MAF are a crap shoot.

[Q45tech]

We always recommend new to them used 10+ year old V8 owners have $3,000 in handy cash to fix all the things wrong with 140k used cars.

Why used cars are sold because they are informed it needs $3,000+ in work to solve a few problems. So they find a sucker.

We recommend a PAID expert inspection so that you can review a few same year models and balance trade price vs repair cost.

It concerns me that you don't understand that these TYPES of vehicles require expensive parts, tires, brake pads, etc and generally cost around $2500 per year to maintain and repair......................of course you can decrease this by 40% by do it yourself if you have $20,000 in tools and test equipment.

[paranoidjack]

I just removed my plenum to change my knock sensors. I consider myself more seasoned than the average shadetree mechanic, but far from an expert.

zer...s-now

[pirenuri2]

Thank you very much for all your advices.

I think I am about the give up hope on this car.

It is now clear to me that Q45 was a really bad choice for me. I knew from the beginning that it is very expensive to maintain them. But I thought the computers on these cars were smart enough to report issues accurately. Maybe I should keep driving until the problem gets worst, only than the stupid computer would tell me whats wrong.

My last hope is to find a good infiniti mechanic in New York Area.

[maxnix]

Or you could study the FSM and read the previous posts.

In reality, the FGY33 is the least expensive imported luxury V8 sedan one can own. 4 cylinder econoboxes will cost a little more than half as much to maintain.

But computers and OBD II are an aid to the wise, not a solution for the ignorant. We all had to learn or give up. Most of us are still learning.

Your choice.

[Q45tech]

Just because there is no MIL light on doesn't mean the previous owner didn't remove the bulb or replace it with a burned out one.FIRST THING I CHECK [during rebuy inspection] will the MIL cycle on off just as Emission Test facilities do.

What codes/precodes does OBDII show.

One must understand that OBDII is /was still a work in progress for the first 5 years and each model had its own quirks prior to 2000.

The point is I don't trust early OBDII totally and always use backup test proceedures as fully outlined in FSM to double check results

[MyQisSick]

Please help.I recently bought a 98 Q45 with 140K. I had no idea what I was getting into. It is definitely a wrong car for me. The car is running rich and it has acceleration problems.

Symptoms are:1- The car stalls when I try to restart if the car is warm. It starts up fine on the second try.2- Acceleration problem gets worst if the car is warm.3- Some mornings it smells like a rotten egg.

FUEL - FIRE - AIR, keep this in mind as you attempt to solve your problem. You also need to be patient, persistent, and passionate about actually fixing your car. Right now you feel suckered because you actually bought a USED car that needs some TLC. So, drop the negative vibe your projecting onto your car, it not the car's fault. Trying to rush through it will cost you more MONEY, emotionally, and TIME! Fall in love with your car by imagining what she will be/was and could be/will once you invest a little time and money into her. Remember you get out of it what you put into it.

I had to learn these things the expensive way, over a few cars, A LOT of TIME, frustrated nights, and a lot of money. Now that I got that out my system, here are my reccomendations.

Symptoms are:1- The car stalls when I try to restart if the car is warm. It starts up fine on the second try.Could be many things but I would start with changing the spark plugs (platinum), check for oil in wells, if there is remove and seal the vc with gasket maker. Change the oil/filter. Replace fuel filter, air filter. Clean throttle body with an electrical cleaner. Clean your IAC (idle air control) electrical cleaner.

Then check the FIRE/electrical. Go to a national parts store and have your altenator & batttery checked. Check the tension on your belts. Remove your starter and have it tested (solenoid). Check out all of your fuses both inside the car and under the hood. 2- Acceleration problem gets worst if the car is warm.Again could be many things, check your fuel line connection points for looseness or leaks. Check fuel regular for looseness or leaks. Check for cracked, broken, or disconnected hoses.

3- Some mornings it smells like a rotten egg. see answer to #2

I don't know if this will solve your problem (IT COULD) but it will put you a LOT closer, the car WILL run better, cost less than $200, you have a PLAN (which eases frustration), and give you good foundation to build on.

Keep us posted, if you don't give up.

Good luck!

Dale

[pirenuri2]

Dale,Thank you very much. It is very encouraging to get help from members that are knowledgeable about Q45s.

This weekend I am plaining on spending few hours on inspecting cables and hoses.

Have a nice weekend

[qship96]

[goody90q45]

......This weekend I am plaining on spending few hours on inspecting cables and hoses.....

Is the check engine light on? If so you should pull the ECU codes. You can buy a code reader cheap ($30 ebay, $100 auto parts store) or pull them manually from the ECU. See page EC-58 in the link.

http://www.nicoclub.com/FSM/Q4...c.pdf

Knock sensors seem to cause acceleration problems on the 96+ Q45's. It wouldn't hurt to ohm the KS to make sure they're still working properly. The connectors should be in a simillar spot to the G50.



Careful about using the stealership for repairs. They like to throw money at parts and it gets expensive quick.

[pirenuri2]

I had my mechanic check all fuel lines and hoses. He couldn't find anything wrong.

This week I will have my mechanic change both KS by removing the plenum. Since a lot of part will be removed during the process, is there anything else we should clean or replace?

Thanks

[paranoidjack]

I had my mechanic check all fuel lines and hoses. He couldn't find anything wrong.

This week I will have my mechanic change both KS by removing the plenum. Since a lot of part will be removed during the process, is there anything else we should clean or replace?

Thanks

Ensure to clean EGR valve and assembly...not the easiest or funnest thing, but it is filthy and should be done.