Q sluggish/hesitating when warmed up

[Mopar]

Hey all,

So I have this problem with my Q. It drives as it should when it is cold. But once the temp gets to the middle where it should be after about 5 min driving, the car loses power and starts hesitating/being sluggish when trying to gas it. Sort of like turns into a 4 cylinder car.

I looked into it and narrowed it down to either knock sensors or oxygen sensors. I know there are some great mechanics out there on this site, so I am asking you guys from your experience what would cause this problem to be temperature related?

Thanks!

[Lokim]

Check out the coolant temp sensor. If it is not reading right (stuck low), the car will run rich (think choke, like a carburetor) because the computer doesn't know the engine is warm.

[Mopar]

Where can i find that sensor sir?

[paranoidjack]

Knock sensors, MAF, o2 sensors...

Is the check engine light on?

[Mopar]

I cleaned my MAF and the intake system. Since it is temperature related i ruled out the ks and o2 sensors. It only happens when the car is warmed up. The car is drinking gas and i mean drinking like a frat brother drinks beer.

My check engine came on and before i could check ran away.

Also in the FSM it says the ECT sensor is by the #2 injector. Where would i find it? Is it by the intake manifold? Can i see it from the engine or do i have to take it apart to find it?

[Lokim]

When I said check it, I meant get a scan tool on it and see what the reading is when the car is warm. The sensor itself is near the thermostat, IIRC.

[paranoidjack]

I'll say it again - KS and o2 sensors. My bet is O2 sensors. Don't rule them out because it doesn't happen when cold - those sensors are minimally used before warmup.

[Mopar]

Okey. Thanks for the inputs guys. I am planning on changing the ETC first, since it is cheaper and easier to replace. If it doesnt make it better, then i will check the o2 sensors.

Jack, I know you did some plenium work, how hard would it be to change the o2 and KS sensors besides the obvious?

[paranoidjack]

Okey. Thanks for the inputs guys. I am planning on changing the ETC first, since it is cheaper and easier to replace. If it doesnt make it better, then i will check the o2 sensors.

Jack, I know you did some plenium work, how hard would it be to change the o2 and KS sensors besides the obvious?

O2 sensors are easy. Knock sensors are not.

[Mopar]

Well i changed the ect sensor and no change, runs a little better but the main problem is there. So should i look into o2 sensors? Could they be effected by the engine temperature? Could they cause sluggish/heavy acceleration and increase in usage?

How much are they from the IOS? can i go aftermarket on them? I checked local autozone the are 100 bucks a pop.

Is there a way to troubleshoot them? Maybe its a bad plug?

[Lokim]

Find the NTK brand sensors, they're OEM. Get the part number(s) from your local auto parts store and search the number on Google Shopping. You'll likely find a better price there. O2 sensors can definitely cause a rich condition if they're not reading correctly, but an internal fuel leak will too.

[Mopar]

Will the sensor below work? Seems like it's OEM to me.

What makes me curious is that when the car is cold it runs perfectly fine. So should I just order and replace all three of them (There are three, right?) or should I change them one by one until my car fixes itself?

http://cgi.ebay.com/ebaymotors/NGK-NTK- ... ccessories

[maxnix]

When's the last time you replaced your fuel filter? What was the replacement interval before that? Using BG44K or SL1? Top tier Premium? Have you measured your fuel pressure at idle and WOT?

[Lokim]

Does the car run better after being run on the freeway for a few miles?

[Mopar]

When's the last time you replaced your fuel filter? What was the replacement interval before that? Using BG44K or SL1? Top tier Premium? Have you measured your fuel pressure at idle and WOT?

Last time was about two years ago. Running on 91 SoCal VERY low grade gas, but the best that I can find around here. I changed my fuel filter today. It was VERY dirty, when I ran water through it, the other end came up dirty, so it was definitely helpful. The car runs more crisp now, ready to gain speed, but that sluggishness is kinda still there. I am thinking all that dirty fuel must have messed up my injectors somehow. No?. I ran some chevron fuel injector with a half tank of 91 today, and so far so good. I want to wait to see what happens within a day or two.

Should I get a BG44K through the tank too?. If it continues doing what it was doing, then I have no choice but to do injectors next. I have a set on a rail at home ready to go in. I was wondering how would one make sure they work before putting them on. Or how can I check the ones that are on the car already?.

I have not measured fuel pressure at idle and WOT (idk what WOT means). How could I do those?.

To the question above this post.... My car feels the same no matter how much u drive on the freeway. Once warmed up it always does that.

Thank you guys for the good pointers, so far, I have remedied the problem to 90%...

[Mopar]

Just ran an OBD scan on the car. It came with 110-IAT sensor should have known!. How can I find the part number for this? I searched autozone they ahve these two. Which one would work the best?

http://www.autozone.com/autozone/access ... ing=search

[Lokim]

Have your local parts store cross-reference this Borg-Warner P/N: WT5065, that should be the right part. I should have mentioned this part, as engine temp. related problems are generally due to ECT or IAT sensors, or bad heaters in the O2 sensors.

[Mopar]

Will do! but is aftermarket ok for this part? or should I get it from the dealer?

[maxnix]

Fuel, cabin and engine air filters should be replaced annually. 2 years is too long for bad gas in the fuel filter with its limited capacity.

[Mopar]

Fuel, cabin and engine air filters should be replaced annually. 2 years is too long for bad gas in the fuel filter with its limited capacity.

Understood. I will defnately change them regularly from now on. Thinking back i remembered all this happened after my brother filled up full tank of 87. After it was done i started getting these symptoms.

Ran injector cleaner, will get bg44 today, the car feels much much better.

[Lokim]

The P/N I gave you is aftermarket. Don't get the Edelbrock sensor. BTW, WOT is Wide-Open-Throttle.

[maxnix]

Will do! but is aftermarket ok for this part? or should I get it from the dealer?

From Joe.

http://www.infinitipartsusa.com

After market ones have proven to be low quality, fail early, and are usually incorrectly calibrated.

[maxnix]

Ran injector cleaner, will get bg44 today, the car feels much much better.

The Redline SI1 is readily available. Use it once a month, at least. Do buy Tier One Premium only from a station with new tanks.

http://www.toptiergas.com

Only accept cash from brother form now on, no gas.

[Mopar]

And check your pcv valve also. I changed that the car is definately much better mine was all dirty...

[Mopar]

Well, after all that, my CEL came on again. Scanned it... You were right. Knock sensors! I bought two they came today from the dealer. Short on cash so I have to do it myself. I have time and toold and do regular maintenance myself.

To those (like jack) that have done this job can u please tell me where to find them? The pic in the fsm is not the best to point out where they are...

And i read that its possible to change the second one without removing the plenum...

[maxnix]

They are in the valley of death. Wait until you can afford hoses and gaskets.

They can be replaced by removing the alternator, but I am not convinced that correct torque can be applied, which is critical to their functioning. Believe me, your plenum and runners and the EGR tube inside all need to be cleaned.

[Lokim]

They are in the valley of death.

I love it!

[Mopar]

Well today I cleaned my TB and what a difference it made. I have almost zero hesitation now, but I still have to replace knock sensors. The FSM is not very friendly to show where they are located and how to reach them.

Anyone that has any info please share. With these gas prices, my q is getting 12mpg and i wanna make sure I can push that number up as much as possible. How can I change these darn KS? please provide details.

[Geothermal]

So, hate to revive a dead thread, but I believe I'm having this same issue in my 2002 Q45. Scanning it gave a IAT temp that starts at 170+ and slowly comes down to about 140. The car stalls very heavily and just will not stay running at times. Tapping the throttle can keep it alive, and slowly opening the throttle as I go will eventually clear it, and it will run relatively smooth, until the rpm drops again, at say a stop. There's also a crazy strong smell of gas and burning oil.

This only happens on days when it's hot and humid out, usually over 75+ and 75% humidity. It runs perfectly fine during every season except summer. Also, only happens at startup. If I drive it all day without turning the engine off, it runs fine all day, but once I turn it off, I have about a 50% chance of it happening, and will keep happening everytime I turn on the engine until it cools off again.

I searched that Borg-Warner PN, but it's for 2001. Would it work for 2002, or should i go with something else?

Edit: I have a picture of the LD and a video of trying to run it.

http://imgur.com/a/E3wjb

Video uploading now.

[Geothermal]

Video link here

https://youtu.be/E9I47mdp4fs