Car stuttering/bucking/almost stalling at idle AND while cruising

Shift518 Automotive
1

Copying my post from another forum…

So a couple of days ago, I’m idling the car first thing in the morning and I notice the RPM’s falling to around 500 and back up to 600. Car is almost stalling but catching itself.

Today, I’m driving home from being out and if I give the car 10-20% throttle (I’m guesstimating)…the car bucks and otherwise doesn’t want to accelerate. If I let off the gas, car coasts perfectly fine. If I give half throttle or more, car moves like it should. Why is it only ‘catching’ in that particular lower throttle range?

I have had a P0171 code for the last 11 months…been trying to fix and haven’t had much luck. However, when I scanned the car just now with my scanner, I got:

P1105 - Generic - Pending
P1105 - Generic
P1105 - Generic - MAP/Baro Circuit Malfunction

My P0171 code was nowhere to be found. Light (CEL) was actually off earlier in the week. Perhaps it solved itself?

I also noticed a funky smell as the car was ‘sputtering’ at idle (I’m outside). It’s not gas, it’s not oil, it almost smells like what the PCV valve does when you pull it out.

I have a spare (my stock) MAP/Baro sensor (located on the intake snorkle) that I’ll try replacing but is what I am experiencing a symptom of that sensor being bad? It almost felt like the MAF (when the MAF is bad it won’t let you go past 3k rpm) or possibly the TPS.

Later on…

Well I changed the MAP/BARO sensor to another one I had (that should be 100% functional) and the issue is still there.

Here is a small clip of my problem:

http://www.anyyouth.com/other/CarProblem.wmv

Car has issues if I’m anything less than 50% throttle.

Could it be my fuel pump/relay/filter?

Maybe I just got a bad batch of gas? Isn’t there some kind of chemical you can pour into the gas tank if the gas is ‘bad’? Dry gas?

2
  1. If you changed any gaskets on the top end, could be an air leak
  2. Could be bad gas, I’ve had it happen to me. Car coasted fine, but bucked and sputtered soon as you gave it any throttle
  3. Check for loose hoses/leaks anywhere.
3
  1. I did. I removed the 2000 Maxima Variable Intake Manifold like 4 weeks ago. Would it take 4 weeks for a leak to ‘happen’?
  2. I’m hoping it’s just bad gas.
  3. I hate finding leaks. I never did find them when trying to fix the P0171 code.

The smell I mentioned above smells like burnt rubber. Car reaked today in the morning. It only starts to smell once it starts bucking/stalling.

4

Well I put in Gumout injector cleaner and STP Fuel Care or whatever and ran the car at idle for a couple of minutes to get it up into the fuel lines…started to stall again but I hope by the time I get to the car at 4:30 (it’s 1pm) it’ll be better. I’m still going to buy a fuel filter though and replace the MAF with another one I have.

5

run a can of seafoam in the tank as well

6

i had the same shit in my jetta people told me the crazyest things and it was the fuel pump overheating

7

its a maxima. cut your losses

8

Maxima’s are actually pretty f’in reliable. ALL of my car troubles seemed to start when I did the manifold swap (I actually didn’t do much, had two guys in NYC who are regarded very highly in the Maxima community do the work). Now that I’ve gone back to stock (one of the two guys did the swap) it’s been iffy.

My first 97 GXE Maxima had zero issues for years (my brother had it before me). These are good cars.

Lesson learned…leave shit stock when it comes to engines unless it’s a project car or you yourself know the ins and outs of engines. I don’t. I should just stick to being show and no go lol.

Anyway…I’ll try another MAF tonight…and I’ll try to see if I hear the fuel pump turn on, etc.

I’ll fix this like I fixed the P0171 code (took a while but I think I finally got it).

9

stock pump will be quiet. you need to check the voltage to the pump. maybe the FP relay is failing. get a mechanical pressure gauge and get your fuel pressure at the rail.

10

Nah my pump makes a buzzing sound for 3 or 4 seconds when it first turns on. This happened on my first Maxima and this one. I’ll take the rear seat out (it’s under the seat) and listen.

I don’t know how to do that (check the pressure or test a relay). How much do those gauges go for? Would it be in the Haynes manual?

11

Another update.

On my way home the CEL starting flashing. That usually equals misfire. I’m going to go out right now and check the plugs/coilpacks. I’m still going to change the MAF and check the hoses and such but it’s probably all misfire related.

12

Well…it ended up being a misfire code (multiple - P0300).

I took out all the coils, looked them over as well as the plugs, and re-installed everything taking good care.

I guess I didn’t tighten the plugs down good enough 4 weeks ago (before the 00VI removal) while trying to fix my P0171 code. This is like my 20th time doing plugs, so I was kinda surprised.

Drove the car. Fine. All RPM ranges.

Idled the car. Fine. All RPM ranges.

13

the problem im spreaking of is very hard to find because its when the pump overheats then cools i self doen enought to run for a little longer you will hear it on start up

14

bad O2 sensor would be my guess

15

people working on cars that shouldnt would be mine

16

you would say that, johnny drama to save the day

17

It was a coil pack/spark plug issue.

Not exactly sure what you’re trying to start (if anything)…

But…

I’m sorry for wanting to save myself money and trying to do shit myself, instead of paying someone like you (a ‘professional mechanic’) who’d might take me to cleaner for something as simple as a spark plug install. We’ve all heard the stories of people getting charged ridiculous amounts of money for something simple.

I happened to not tighten the plugs all the way last time. I am human.

What business is it to you anyway? I fixed the last problem (P0171 - hasn’t been lit in a couple weeks now) without going to you for help, I’m pretty sure I can handle fixing anything else with time (this issue). This isn’t the first time you’ve posted something like that, insinuating who knows what.

Relax, we’re not all as perfect as you when it comes to working on cars. I’m learning. One day, I pray, I will be able to do even the most complex job with the ease of which you do it.

Hate to be an ass but seriously man…was your comment necessary?