VX misfire and stall under load

[finko88]

Hey guys, wondering if someone has seen this before. My VX S starts a little rough, at times it idles quite rough (otherwise its idle is normal), but when revs are applied, it misfires and stalls. Its completely undrivable. Doesn't matter if its in neutral or in gear, you apply enough revs, the engine dies. That said though, if you can manage to push the revs up to about 3.5k to 4k without it stalling, it drives with no problem (only managed to do this twice now).

List of parts that have been tested/replaced:

*fuel pump
*fuel filter
*spark plugs
*leads
*coils
*air filter
*throttle body
*maf sensor
*all related fuses and relays
*fuel injectors
*fuel lines
*egr sensor

as far as I can tell, the engine is getting fuel, air, and spark. Which makes me think it must be either exhaust or computer related. There are no engine lights of any kind on. The exhaust makes a bad "pop" sound, a really bad misfire, but when you manage to get the revs up and it sounds ok, the exhaust still pops. Is there maybe a valve or something in there that could be stuck? I couldnt find anything online

Any help would be greatly appreciated

 

[EYY]

Change your dfi module, usually fixes that problem.

 

[Turtl3]

maybe it could also be the tps?. but more likely what eyy said. dfi module

 

[The1]

sounds like it's to rich if it's popping, likely a dead o2 sensor or 2. You checked for fault codes?

 

[devilly]

if you can hear popping at exhaust then you have an air leak in the exhaust system.

first tighten the nuts on the headers and check see if that fixes it if not then work your way down the exhaust system.

 

[Combat Wombat]

My guess is the O2 sensor as well. Good luck....it worked for me.

 

[finko88]

Thanks for the advice so far guys. Turns out its not the dfi or the o2 sensor. This is really doing my head in

 

[devilly]

put in some injector cleaner,ruff idles e.t.c is usually the vacuum lines 3 at the back of plenum and the ones on the throttle body.

can try putting on small zippy locks then if it goes away look into ring clamps.

also try tightening down where the exhaust meets the engine.

 

[finko88]

Hopefully this brings the thread back up. Im at my wits end. I gave up on it a while back (lack of funds) but over the past 2 weeks ive given it another shot. $600 on mechanics and parts later and its still no different

Under mechanic advice I replaced the IAC and the TPS, as well as cleaning the s**t out of the throttle body, no difference. Replaced the hoses running from the throttle body, nothing. The fuel was low so I topped it up with 98 octane and threw in some injector cleaner, no difference.

Error codes brought up 0012, which i believe means no problem. Pigs ass i say

The only other thing ive heard either on here or in the outside world is exhaust, but I work at a performance r&d and warehouse, and the boys at work assure me it cant be exhaust. If you guys cany think of anything else, ill give it a shot, but any further ideas would be greatly appreciated

Im legitimately at my wits end. I love this car but im an inch from scrapping it and cutting my losses

 

[Tonner Matt]

Have you tried replacing the crank angle sensor and the cam angle sensor.
I suggest you replace these together, my reasoning is this # I have seen it a few times where the crank angle sensor was replaced, the car runs great then 2 or 3 days later the cam angle sensor plays up. Have also seen cars that don't throw any codes for these 2 sensors, run like new after they were replaced.
Some people may not agree with my idea, but these are just my observations over time
You seem to have replaced or checked pretty much everything else, at this point what harm could it do to at least give it a try