What to do next... 94 540

[byurko]

I've been dealing w/ a rough idle and intermittent check engine light. Not sure what I need to do next!

So far I've pulled the intake manifold and replaced the intake manifold gaskets, the PCV plate and the throttle body gasket. I've cleaned out my ICV. I thought I had fixed it!!

On my drive into work this morning, it started running rough again and threw my check engine light after about 5-10 mins...

O2 Sensors need replacing? MAF sensor? [scratches head!!]

I'm sure a lot of 530/540 owners are dealing w/ the same issues right now as they're all about the same age/mileage - I have 130K on the clock.

Bryan

[Tiger]

You said you cleaned your ICV? Why didn't you replace it? Leakdown test is what I would do next.

[byurko]

Alusil block - was replaced around 79K miles...

How much does an ICV cost? Will it cause a check engine light?

Bryan

[632 Regal]

Bryan, have to disconnected the battery for a half hour to reset the computers? You should replace the spark plug boots also, when did you do the plugs and has the injectors ever been replaced? WHen they swap blocks they usually just swap the old stuff over.

I would try the disconnect thing first. Go pull the cable and put it back on when you go home and see if it helps.

[byurko]

I actually just replaced my battery w/ 49-DL from AutoZone b/c my 2yr. old son had been in my car "playing"! Didn't realize the door was still open until the next day! Anyway, it drained my battery again and wouldn't hold a charge.

I sprayed the tips of the injectors w/ carb cleaner to get all the "gunk" off them - they were shining when I reinstalled them! I guess the injectors is a possibility though!

The spark plug boots look like new - no cracks and very pliable rubber.

Bryan

[632 Regal]

disconnect the 'fully' charged battery for a half hour anyways.

when I first got my car I replaced the plugs, injectors, fixed air leaks etc etc... still had the Nikasil miss until I finally got the plug boots (much cheaper than the prior). Mine were all new and pliable too, just must have had some internal resistance in a couple.

[salansky]

I would check for a vacuum leak. During cold morning starts last jan/feb, my 95
540 did the same thing. The car would not want to start or idle and would cough and throw the check engine light too. When it warmed up, the hoses would get pliable and seal better and the car would run OK. Turns out I had some pretty major leaks coming from some hoses. I don't recall which ones were swapped as I had my indy do it during an oil change service. She has been starting and running smoothly ever since.
-jack

[byurko]

Thanks Guys! It starts fine and idles a little rough - like a normal 540! Will only throw a check engine light and really run rough once it warms up... Sounds like the O2 is bad??

I did check all of the vacuum hoses when I had the intake manifold off... And ended up replacing one (about 3ins long) right off the throttle body.

Bryan

[632 Regal]

the reason for the batt disconnect is to rule all else out, next step is replace what needs it, re-batt disconnect, codes again then do the O2 sensors. A lot of people replace the O2s just to find out it still throws the codes from something else.

[byurko]

Thanks Jeff! I'll disconnect tonight to reset...

BTW, I averaged 12.5MPG on my 20mile round trip to/from work - I usually get about 17-18MPG on the same drive.

Bryan

[632 Regal]

yep threw a code and is running limp, af everything else checks out like I mentioned then you can try the O2 sensors, just that 100 bux each is an expensive test if that isnt the culprit. Trying to save you some grief.

Good luck!