Folks,

I experiencing a rough idle and during low speeds and cruising feel hesitation from the engine. Under load the car feels fine. Plugs and coils are fairly new in the car. I have a durametric and looked at misfires, since this is what it sounds to me during idle. I have no CEL. At cold start I see multiple misfires in all cylinders. There is a misfire counter which goes into the thousands. Is this normal? Anybody able to guide me on what I should read out and what is normal and abnormal?

Thank you very much!

Thank you for your response. The battery should not be too old. Also, if I am not driving the car I always put it on the trickle charger. I did not look at the MAF but measured the voltage at idle which was around 1V. Hope I am not wrong but it seemed to be in the range it should be. Vacuum leak, yes, maybe. How to test for that? If I am not mistaken there should be crank case vacuum. When I take the oil cap off at idle I cannot feel anything. What negative pressure should I expect at the oil filler cap? A range of values would be great. Does anybody have insight?

I’d also check the battery. Had a car running rough and replaced it recently and it genuinely runs better now.

Checked the battery. Seems to be ok. I would greatly appreciate if someone could check with their durametric what misfire data they collect. Also if anybody has an idea on what other data I should take a look at. Thank you very much!

Fuel pump? A bad hose? Intake manifold hoses do crack with age and there's lotta them. Bad gas.

FYI. When my battery was tested it showed ok on the volt meter.
‘It was only when they used a special load tester that they identified it as the problem.

Thanks for the suggestions. It’s not bad gas. Filled it already twice and it did not change. With hoses, do you refer to the vacuum hoses? Any idea what vacuum I should expect? Also still looking for the crankcase vacuum. Nobody aware of what range it should be in or if it can be felt when the oil cap
is removed during idle?

Thank you very much in advance! Could you also please check if you feel a vacuum when you take off the oil cap when at idle. This would really help.

i checked the MAF voltage with the durametric at idle. Got less than 1.1V which I assume is the magic number. Also disconnected the MAF to see if there is any change at idle. Got some initial studded, some higher rpm and a code but after a couple minutes it went back to the rough idle with misfires. However I also bought a can of cleaner and will try to spray the can in it on the weekend. Please let me know if there are any values that i should read out with the durametric that would help diagnose the problem.

Oh one thing... I have a fabspeed catback max flow. Big ham style mufflers are eliminated. The solenoid that is used to open the exhaust flaps is capped on one port and disconnect from the power. The lower port of the solenoid is open. Is that supposed to be the case? Did something fall off? Thanks!!!

yes, that’s the solenoid I was talking about. It has two exit ports. One to the right which I guess goes to the vacuum thingy at the exhaust and one at the bottom. The right port is capped. The bottom is open. I will put a cap in that. What is the bottom port used for? Do you guys have the wire plugged into the solenoid or is it disconnected?