Z22se misfire, poor idle

Rossy1981 · January 21, 2018

Hi all, new here and i need a little help with my vec c z22se

Car has 136k miles on the clock and has always been maintained and ran faultlessly

Last week she started to have a slight rough idle that gradually got worse. Eventually running on 3 cylinders and sounded dog rough.

I replaced the spark plugs and bought a new coil pack and things have improved a lot, although the rough idle is still there but is running on all 4.

Also on hard acceleration she misses every now and then and i can tell its down on power with the hessitation showing itself every now and then. also on the motorway the engine light will blink and then i'll ease off and the light will go out

I plugged my cheap obd reader in and had codes ranging from p0300 to p0304 so ive cleared them and its still the same.

I've changed the coolant temp switch too as i read they can cause problems.

I'm at a loss on what to do next as like most, my funds are slowly being dried up with what not and i need this fixed

Things done
1. new coil pack
2. new spark plugs
3. new coolant temp switch
4. EGR blanked and turned to the side (done last year)
5. throttle body cleaned and all seems ok
6. oil/coolant levels are spot on

I need to get an opcom scanner when money allows this week unless anyone local can help? (Reigate)

Many thanks in advance

ob one · January 21, 2018

I know what that is like see if you can get the map sensor checked been down that changing parts route

Rossy1981 · January 21, 2018

ob one said:
I know what that is like see if you can get the map sensor checked been down that changing parts route

Thanks I'll check that out

Out of curiosity where is the map sensor located on the engine?

ob one · January 21, 2018

just behind throttle body

ob one · January 21, 2018

when I started my car and pressed down on the sensor it would misfire like it was running on n two cylinders and abs light would come on

Rossy1981 · January 21, 2018

OK I'll have a look. If I unplugged it would theecu resort to a base map or would the engine go crazy?

Think I deffo need to order one of them opcom readers off of ebay

ob one · January 21, 2018

don't know about that no expert just had similar problems mine did that and I had only done 2oo miles on a new engine lol

Rossy1981 · January 21, 2018

OK thanks for the help so far its much appreciated

Rossy1981 · January 25, 2018

Still the same

Car is idling round 750rpm with a pup pup pup sound from exhaust.

Once warmed up the idle hiccup is less noticeable. it's strange as when warm it pulls like it should now with plenty or torque I just dont get why the idle is so erratic

I keep getting a camshaft postion sensor code but i thought the z22se didnt have this fitted

I think i might try a tb clean and start replacing other sensors to narrow it down

Any other suggestions for me to try?

I tried an opcom reader but it wouldn't work as something was broken inside the reader and rattling

KevinH · January 26, 2018

Did you replace the coil pack with a genuine GM one?

Edit:

Rossy1981 said:
I keep getting a camshaft postion sensor code but i thought the z22se didnt have this fitted

The Z22SE's don't have a camshaft sensor - the genuine coil packs have a CSI (Compression Sense Ignition) sensor which was developed and produced by Delphi. Aftermarket coil packs don't have the correct sensor and usually produce error codes.

ob one · January 26, 2018

try checking if you have any air leaks on inlet manifold

Rossy1981 · January 27, 2018

Original coil pack back on the car as pattern part made it run worse

Maf cleaned and has helped smooth things out further

However yesterday I was checking the oxygen sensor and when I moved the sensors wire the car ran perfect so I think my culprit is the oxygen sensor on the manifold. the loom for the car is in very good condition so I think I need a new sensor.

Does the oxygen sensor work from the get go? Or does the engine have to be warm to enter closed/open loop?

Rossy1981 · February 11, 2018

front oxygen sensor replaced and still the same

Im thinking i might have a dodgy throttle body as when i replied last about the wire on the o2 sensor, i had cleaned the throttle body that day too.

if i start the car with the air hose off, i can watch the throttle body moving back and forth trying to adjust itself. The throttle body is sparkling but i think something may be amiss inside the electronic housing.

Wouldy a dodgy throttle body cause a poor idle and hessitation on acceleration?

Seriously getting ticked off with the car and i may have to end up with chucking it into a garage. i cant get my opcom to connect as i think the reader is duff. If anyone is local to Reigate could anyone help with reading my live data?