can a poor battery ground connection cause a idle issue? idles low at a stop once it is warmed up. battery was disconneted for about a week or so because i was waiting for a starter to come in from the dealership. no check engine light....im just so frustrated with this car right now...
any help would be great guys

 

a few notes

when you disconnect the battery for more than like 10 min. it resets the ECU and can take a day for it to get back to normal, but usually idles higher, not lower, you could also try adjusting the idle with the screw on the top of the throttle body, if it was a bad ground id assume the car would either run or wouldnt, but I could be mistaken

 

well im tuned so the idle was up a bit anyway due to the cams. for a smother idle....i replaced the egr valve awhile back and really have had trouble with the idle ever since. checked vaccum lines. it ran fine for awhile and then threw 3 more codes, egr one again ,some o2 sensor one and camshaft position sensor. so idk what to replace if anything. it seems to be out of "limp mode" now but of coarse still have the bad idle issue with no SEL so im just boggled lol...ground terminal is kinda cracked but stays put when you screw it down thats why im asking. i have to replace that terminal anyway

 

jeez the cam sensor is critical, do that first

 

Cam sensor first, as stated above, and since you have an 03, check the IAC. I had a bad idle problems and it ended up being the iac was broken.

 

iac whats that?

 

idle air control. its kinda round and at the bottom of your intake manifold right underneath your throttle body

 

bump

 

by the way, do you know where the cam angle sensor is? incase you dont, its the sensor sticking out of the right corner of the engine cam cover area (hanging in the air near the exhaust manifold)

did you make sure both vacuum lines going to the EGR valve is tight? if you are familiar with ecuclash, check what target RPM you are set at. if you are idling higher or lower, you can attempt to adjust with idle screw(located on top of throttle body). if you try to adjust it differently then what ecu whats, the IAC will be constantly working to fight you.


also FYI once the car is running, it doesnt really rely on the battery. if you can crank and start the car without issue, then poor grounding to the battery would not be caused by bad grounding. poor battery grounding would reduce/prevent your alternator from charging your battery and cause starting issue down the road.

 

i had the same problem i replaced my iac and it helped a lot its still not perfect and i stall sometimes (usually after going in reverse not sure why haha) but i got it pretty cheap off here and it was an easy fix always check easy stuff first save yourself some time and money

 

ok guys update....had emmisions test today and it is still running like crap at idle but it passed lol. no check engine light still of coarse. went to autozone to see if any codes where saved or pending or whatnot, and the p whatever insignifigant (cant spell) air flow for the egr valve came up again as a pending. just changed this a month ago or so. checked vaccum lines going to egr valve and they are fine. what else could it be? isnt there a sensor to control the egr valve? i need help

 

i had issues wit mine and changed my cam position sensor... car drives like a new benz now lol.. a $70 part and a 2 min. fix well worth it..

 

did it throw a coDE DREVO?

 

ttt

 

now light came on and now its the same egr code and now maf sensor...i wish this car would make ups its mind on what it wants me to fix.....thoughts