car stolen my money

jade18

lol ok got your attention, im pulling my hair out with this and have been and asked everywhere before bothering you guys with this, but im really at the end on my tether with it
heres a quick run down
astra coupe 2.2 51 X reg
100K on clock
pretty well looked after

i have random engine shake/judder possible missfire?? im not sure, it gets worse the hotter it gets. it starts fine, it drives ok, perhaps a little sluggish and under powerd for a 2,2 but as its my first one im not to sure what it shoudl go like.
sometimes it cuase the engine to all most cut out, then it over revs to accomodate this and ends up almost cutting out completely so i have to raise the revs for a short time and slowly let them drop back down to a smoothish idle
when it first starts from cold in the mornings it runs quite well but once it starts getting hot it soon starts to get worse and runs quite lumpy

the first things i did when i got it was timing and balancer chains and tensioners etc. i flushed the engine and replaced with the recomenned gm oil
then replaced the plugs, then flushed the fuel system. at this time i also added a straight through 4 inch exhaust from cat onwards.
this is when i really started to hear the engine misfiring as the exhaust makes a popping noise when i take my foot of the acellerator, sounds like unburnt fuel exploding in the exhaust
all this time the car has been doing the misfiring problem
so orderd a egr cheater and blanking plate, fitted and problem still exists
removed and fitted front lambda sensor, problem still exists
changed coil pack, problem still exists
cleaned throttle body, problem still exists

now have access to full diagnostic equipment so thought bonus now i can get it sorted.
run a scan and NO faults found. i dont know how to use the equipment other than just checking for fault codes to be honest so cant go any further into it from here

there is no excessive smoke from the exhaust to indicate stem seals or anythiging like that
it awlways starts first time without and problems

what am i missing guys please help i have thrown loads of money at this car that really didnt need to be spent on it and i just dont have any more left to throw at it now
the exhaust i have put on is looking quite carbonised but i assume its down to all the exsessive fuel being burnt off, oh and its juicy as fook, i know its a 2.2 but damn it dont stop drinking
i even started to wonder if someone is draining the fuel out at night for there own car lol

please help guys im desperate

MikeS

blocked cat perhaps

ideally a read out from your sensors would be a good idea and if poss posted up

jade18

i will get a scan again tommorow and upload what it gives, does it make a difference if the engine is running or does it not make any difference to the read out
sorry for my ignorance im not very clued up with mechanics, but since having this car i have learnt a bit

MikeS

let it idle for a bit and warm up and just copy and paste sensor data into forum

i would though think about dropping the downpipe from the manifold and see how u get on

jade18

thanks for your help. i will post up that info tomorrow
if there was a problem with the cat would it throw up a fault on the ecu? or possibly an emissions fault?

JohnnyN

Not always. There have been a few posts on here in the past where the cat has been blocked or broken up yet not given an error. Are you still on a standard cat? Its possible that the unburnt fuel you've mentioned has damaged the cat. Standard cats are ceramic where sport cats are metal substrate.

sandyc

If it's only happened since the timing chain was replaced it may be possible that one of the cams is incorrectly timed. All it takes is 1 tooth out to cause such problems. Ask the garage that installed it to re check the cam timing.