Positive fuel trims indicate that the ECM is having to add fuel to obtain the commanded air-fuel ratio.

It could be things like:

A small vacuum leak
A dirty sensor
A partially plugged fuel injector
A weak or failing fuel pump

Ect ect ect

 

On my live data I see a constant 58psi so fuel pressure seems ok? I’ve cleaned the maf sensor it’s a very strange design? I just changed my ignition coil again today was getting a misfire but no codes and sometimes random misfire code. Changing the coil seems to have smoothed up things a lil but not 100 percent. It feels like a lurching pulsating feeling in drive at times. Also changed valve cover the whole cover? Confused?

 

Has the been engine well maintained? Spark Plugs, Throttle Body cleaning, Fuel System cleaning ect

 

Yes spark plugs changed ngk iridium cleaned throttle body all of the above. Just having a rough idle which is also affecting my transmission shift points.

 

I'd take a look at the fuel injectors. Surging at idle could also be a vacuum leak. Did you get a genuine GM cam cover? Check all the hoses. A lot of the plastic hoses are known to crack. Go around and check them all. I hope you get it figured out.

 

I had a genuine replacement at first and then I went aftermarket same result no difference tbh. I have done the timing and phasers I did get a code this morning will update when I replace it . I changed the intake but not exhaust.

Ok

 

 

Trim loooks good .. if wasn’t your injectors what about the “plastic intake manifold”
or voltage drop somewhere..
Gas pedal is electronic not cable so perhaps a slight delay there .?

 

It’s like when I’m idling I have a lot of vibration it’s like the engine is pulsating. To me it seems like a misfire but no codes maybe 🤔 jus maybe it could be my plugs I’m running ngk 6418 instead of. Ac delco 41-122 any thoughts???

 

Engine mount(s)?

Enough misfires to make the engine pulsate WILL throw a code.

 

I’ve changed the mount on the passenger side. Let’s say pulling up to a red light a slow roll it feel like I’m driving a cammed v8 ? The car jerks foward something is off

 

Automatic or manual transmission?

 

Automatic

 

What would cause a rough ride I jus changed the shocks could it be control arm or tires ??? Steering also shakes and pull to the left ???

 

A rough idle is not caused by any of those things. The reason I asked out the transmission is that the automatic transmissions actually shift into neutral at a stop and the shift back into park when you start to release the brake.

Did you ever do a compression test?
I think I remember maybe talking to you about that.

 

Update still haven’t gotten around to doing a compression test but I just changed over my NGK6418 spark plugs toAC Delco 41-122 and my idle is still rough 🤦‍♂️ This is very confusing could it be my ignition coil I have changed it twice already same result??)?(?) It feels like a misfire I have tried a smoke test but I didn’t find any leaks

 

Update still haven’t gotten around to doing a compression test but I just changed over my NGK6418 spark plugs toAC Delco 41-122 and my idle is still rough 🤦‍♂️ This is very confusing could it be my ignition coil I have changed it twice already same result??)?(?) It feels like a misfire I have tried a smoke test but I didn’t find any leaks

Also I just changed my brake booster vacuum switch made a big difference in safety 👍

 

Still in need of help with this problem. Car has been idling rougher I really don’t understand what’s going on the other day I got a p0171 and p0300 and p0455 Already changed the purge valve and gas cap but I do get a message occasionally saying tighten gas cap ??? Shifts are rough 🤷🏽‍♂️ I don’t understand why 1.8 idles so rough

 

So a new issue my fuel trims are high around 20% at idle but when I unplugged my maf sensor my levels went to around 3% 🤔 which is normal. When I plugged it back in my levels went to around 7%. Could my MAF be the problem ???? I tried cleaning it before but no success.

Also randomly got these two codes when my fuel trims were high around 20%

 

Hello still need help with my issues here’s an update car still runs rough also shifts roughly as well. I occasionally have been getting a p0455 code and I already changed gas cap and purge valve ? My main issue is the bucking at idle. I have high long term fuel trims at idle and when I unplugged maf sensor my fuel trims went back to normal any ideas ???

 

Ive got a 2011 Cruze 1.8L and I have the exact same issues its crazy! Cannot figure it out for the life of me. New plugs, new coils, cleaned MAF. Did you ever figure it out? Lemme know please.

 

Check the transmission fluid. Please let me know what you find.

 

Your rough idle sounds to me like your air fuel mixture equipment has an issue somewhere. Could be your mass air flow sensor, knock sensor, throttle position sensor, purge valve, on and on ad nauseum. I had the same thing happen to me iny '13 1.8. When I would come to a stop, the car seem to want to surge, release, surge, release over and over. I put a quart of transmission fluid in it and it stopped surging. I still have my at idle on startup problem to replace the purge valve sensor today. Already replaced the knock sensor, and this is a pretty cheap second step for me, hoping I don't have to replace the mass air flow sensor as those bad boys are pretty expensive. Hope this helped some, and good luck.

 

Check your spark plugs and your negative cable on your battery, some first gens have a problem to ground causing a failure on start sometime, My car has this issue as well ONLY problem in 11 years of owning her and done tons of mods to her!

 

Okay, how should I diagnose this ground cable.
Please read my post about everything ive been doing. 2011Chevy Cruze 1.8L Throttle issue

 

2012 cruze 1.8 here. Shaking at idle felt through drivers seat. Also when I rev slightly higher rpms say 1500 it occasionally surges approx 100 rpm. Changed plugs and coil GM OE. Had replaced valve cover EGR a couple years ago. Thinking engine mount or fuel injectors. I don't see any major issue with mount but who knows. Will run some injector cleaner and cross fingers.

 

Did you ever fix it?

 

Rough idle in drive. SOMETIMES Chevy Cruze 1.8L 2014 LS (65k miles)

I have had this car since about 35k miles has been great doing! All recommended maintenance was kept up to date etc. Then an engine code for the thermostat appears and that day seemed to be the start of all my problems HA. Replacing the thermostat and other due maintenance was in order..
After replacing the thermostat or honestly maybe even before said repair the rough idle began.

EVERY NOW AND THEN chunking and jumping like a wild big cammed car, putting the car in any other gear other than drive- the problem will go away.
On normal days it is not as smooth as brand new but fairly good. On good days she'll idle perfectly like straight from the lot. THIS IS AFTER REPAIRS MENTIONED BELOW
Super picky...(possibly the weather/angle of car/car temp)

Things I have noticed are- usually happens when the car is at optimal operation temp and it seems the idle RPM drops a tad when the shaking occurs and apply a little bit of gas will get the shaking to stop.

MAF/fuel pump/gas cap are next I guess with a extra eye on vacuum leaks/exhaust leaks?

MAINTENANCE(mostly OEM replacements)
~Thermostat/thermostat housing(cracked and was replaced with a metal one. Only part that I used that was not OEM. The Throttle body heater inlet pipe that sits on top of the thermostat broke so that had to be replaced. SUPER brittle)
~Valve cover(I found what seemed to be a pea size of oil (or fuel) on top of park plugs 2 and 3 replacement fixed this issue since)
~Spark plugs, coil pack
~Water pump(whining/possibly failing)
~Serpentine belt/serpentine tensioner
~Timing belt, timing belt tensioner/idler (heard a ticking noise from this side of the engine and got lucky the idler bearing was shot and when shook rattled. when replaced ticking went away)
~The entire air intake manifold(Had issues with the tuning valve arm coming off, then the actuator not moving so even went to the lengths of replacing the actuator before the entire manifold... This did not work as I kept getting NEW engine codes for the air intake manifold since its been replaced the code has gone away)
~The back VVT sensor (dunno why lol, hoping for blind luck?)
~Knock sensor(under the air intake manifold, why not)
~The coolant reservoir(cracked).
Motor mount looked in okay shape. MAF and throttle body have been cleaned. Fresh oil with no visible leaks/oil looked good when drained. No coolant leaks either after reservoir replacement (pressure tested)/also coolant looked good with the multiple times I had to drain it/bleed it. No engine codes. Do not know if a exhaust leak is present however... *

Definitely a beginner tree shade google mechanic so any advice would be appreciated.
Thank you!