Morning, need some help, got a 1997 VT 3.8L which has a dead miss at idle mostly evident when in drive only with your foot on the brake. On start up the vehicle will idle very rough and some times stall, when starting up for the second time the vehicle will run normal. There is also an intermittent miss when driving at about 2100 rpm when crusing along. Vehicle has recently had spark plugs, leads, fuel filter , crank angle sensor all replaced. The coil packs and DFI have also been removed and replaced with known good ones and issue is still evident. Anyone got any ideas?
Yes that has been checked and cleaned and all pins have been checked to made sure that they have not spread and are contacting properly
Someone mentioned something about the fuel rails that can cause an issue like this, if they've recently been replaced or something. I can't remember exactly word for word what was said, but they basically said that if you've just switched over injectors, and replaced the fuel rails at the same time, that the rails could have rust build up in them, because they're only made of steel, and not alloy like a lot of people think. The issue in the post that I'm referring too, was pretty similar to what you're reporting, but it sounds as though you did say that it was happening before you replaced the injectors and stuff, so I'm assuming that you haven't recently replaced the fuel rails (unless you've somehow got some sort of build up inside there, which was also mentioned could happen, and therefore cause this sort of issue) I'm assuming that you've cleaned all of the other things that might possibly be causing a rough idle, like the IAC, MAF sensor, IAV, and all of those things? I'm not saying that this is the cause, but it might be worth just checking them too make sure that they're ok
The vehicle has been put on the computer and there are no codes coming up, it has had the values for the air flow sensor and air temp sensor also checked, has had extensive throttle body clean and the base idle reset
That voltage is fine. The ECU's have been known for problems like that. I'd check that with a loan one.
