Engine miss only problem I got now

[aussieghostrider]

After spending a few grand on the car in last few years and still under 220,000kms , theres no point buying another car.

Got a new cas and fuel pump cars running ok but I want to know what could cause a small miss and low idle.

The car when cold isn't to bad but after driving a while if Im stopped at set of lights then light turns green and i take foot off brake and just let car idle roll it sort of jerks slightly but not too bad but i notice it.When car is in park and I gently press accelerator just a touch you can hear a definate miss but when revs higher its all good even high speeds up hills no problem.

What could this be...

things done in last 6 months or looked at -->

fuel filter
fuel pump
Oxygen sensor replaced
CAS
spark plugs
leads
air filter
oil / filter change
cleaned throttle body
injector cleaner
pulled engine fuse for 5 mins



The coilpack and module are 100% from the factory I know this as car was mums and was bought new and I know whats been fixed etc.Coil pack I had someone swap it over but miss still there but module has not been touched yet.The injectors were taken out around 2 years ago and serviced and 2 were replaced completely and other 4 were given new filters etc cost me $300.I was reading that aftermarket injectors causes a miss at low idle but are ok at high revs so this could be my problem or one of the injectors is now completely fubar ?

Also the ngk spark plugs I put in myself thinking would help but didn't , I did not gap them though.

coolant temp sensor to ecu was replaced 2 years ago

Im thinking could be -->

replace injectors completely with new ones <--- First thing going to get done
replace IAC
Dfi Module


What you guys think ?

I can live with it if I have to but I would like it running like it did a year ago , like a new car.

[centy]

reco injector on ebay cheap ($80)
does the idle speed remain constant.
check the rubber vac lines for hardness and splits first.
I have seen some so hard they have the snapped off.

[89berlina]

I had similiar symptoms of vibrations as you have had. I replaced the same things except I havent yet changed my injectors. What I replaced, to help you understand my situation was: Fuel pump, CAS, Ignition Module/Coil pack, ECU, Spark plugs, Leads and what I also did was test some of the electrical circuits. What I found, that totally fixed the problem, was that there was a bad (bad=open circuit almost!) connection in the circuit between the MAP sensor and the Throttle Position Sensor. In other words neither were working properly, if working at all! Look at your wiring diagrams (if you have a Gregory's manual this will help) and test the circuits for ohms-resistence. Once I found this problem I fixed it by bridging the circuit with a new wire. Since then the car ran smooth as! If you test your MAP sensor and TPS they will be fine but the circuit may be stuffed. It must have been one of Holdens stuff ups, where they didnt make very good connections in the circuits in the VN's

[greenfoam]

Sounds like a simple sensor problem really, I'd agree withthe above post swap the tps with another one and the map sensor and throw some injector cleaner in it. Pretty likely one of those will fix it as both those sensors have a heavy influence on things just as you start moving the car

[King_berald]

I had similiar symptoms of vibrations as you have had. I replaced the same things except I havent yet changed my injectors. What I replaced, to help you understand my situation was: Fuel pump, CAS, Ignition Module/Coil pack, ECU, Spark plugs, Leads and what I also did was test some of the electrical circuits. What I found, that totally fixed the problem, was that there was a bad (bad=open circuit almost!) connection in the circuit between the MAP sensor and the Throttle Position Sensor. In other words neither were working properly, if working at all! Look at your wiring diagrams (if you have a Gregory's manual this will help) and test the circuits for ohms-resistence. Once I found this problem I fixed it by bridging the circuit with a new wire. Since then the car ran smooth as! If you test your MAP sensor and TPS they will be fine but the circuit may be stuffed. It must have been one of Holdens stuff ups, where they didnt make very good connections in the circuits in the VN's

i think ive got the same problem..
how do you test curcuits???
where are the curcuits??
im absolutely hopeless with electrical stuff like that...