about a month ago I have been experiencing problems at idle very rough, and would slip when i mashed on the throttle more than a quarter. when it warmed up it would go away.



I took it in for a transmission service and oil change after, a week later i changed the spark plug wires to Bremi ones, subtle difference as the wires were old, but problem persisted.



Moved on to spark plugs (free from FCP EURO thankfully) changed those, fired up still no fix, matter of fact the problem is worse.



I scanned the car and was getting a cylinder 5 misfire p0505 i beleive and also and idle control something, can’t recall the exact code, will update with all codes present.



Anyway I was suspecting a vacuum leak but an indy took a look at it, the (ONLY ONE I trust, older german merc tech) and after plugging in his scanner he narrowed it down to fuel injector issue, which could explain the problem getting worse.



Fuel injector cleaner made a slight difference but barely noticeable.



Also last night I drove after a couple cycles to try to get the fuel injector cleaner through and the car kept giving me “convenience functions disable” and then when i turned the car back in after parking (had to go to the bank a mile away, it froze like it was dead, then suddenly restarted , clock moving backwards radio on when it was off before, and it turned on. Drive home ESP light came on, first time that happened.



Known issues: Leaking valve covers, plan to fix after i get this problem sorted

​vent near gas fill up is stuck open so gas smell comes from outside



X pipe was just fixed after a bolt came lose and had it dragging



TLDR: Question: any ideas on what the problem is, anything to check, what could be wrong, and what to do next myself, if anything? I am moving so this is not the best time, and i gave my daily to my mom for pandemic issues. The engine has under 160k mikes and seems healthy when running proper. If this idle Issue can be fixed it’s an amazing car but I can’t figure this out. any suggestions? if it is fuel injector 5 what is reasonable for that fix, i saw the diy and it’s a little out of my pay grade and im tired of busting my hands past month.



ALSO, Anyone in SOUTH FLORIDA who knows or WORKS on these cars, please refer me or i will even help fix this issue, tell me what beer cigarettes and food you like and we can get to work

 

Star Garage in Margate, ask for Joe.

 

Actually I got my Trans service and oil change done there since it was already on the lift.

Everybody requested for me to go there, thing is STR GARAGE is very busy, I hate saying that i wasn’t totally satisfied with the attention that was given when i went there. Im sure they get cars in and out fast but they didn’t take the necessary time to diagnose the idle or even really look at the scan tool long. I told them the multiple problems on the phone that we could look at itamd diagnose it from there. Basically got me in the door, but when i got there their first goal was to take my keys and get whatever service done and get it out. I get it, they are busy but by the time I got there the car idled normal and they just moved on to a transmission service (also got to hear the mechanic tell the front desk how ****ty my transmission is running in front of everyone waiting in the office. don’t care what they think just though it was a little disrespectful but whatever right). Also everyone got a car wash except for me, I wonder why. It seemed like they like customers who don’t know that much about cars and can charge anything, I heard a quote for $500 just for pulleys while i was waiting. less than the dealer but not by much.

NOT to totally Bash STAR, im sure they have good people like Joe, and a reputation for a reason, I just felt like my experience was a little different and they we’re ready for me to get out of the door by the time i left. unfortunately i wanted to love STAR based on what everyone said and that my car went there before but I definitley felt like another “dumb customer” and left feeling like i wasted my money for nothing to be addressed, (almost $400) so im hesitant about them. Sure they are great though, heard lots of good things, just my experience.

 

There is only one part left that fires the plug....ignition coil. Change that and see what happens as I think that should fix it unless its internal issue.

 

While I do have those from FCP Euro under warranty shelling out 500 mail in rebar isn’t fun, would u suggest, changing just cylinder 5 coil pack?

 

Not yet. Swap cylinder 5 coil with another and see if the miss fire moves to another cylinder. If it does there's your problem. If not than start looking somewhere else.

 

thank you! gonna start with this, can’t hurt,

will keep thread updated👍🏾

 

Switched Ifnition could 5 & 7

Before switch:
P0205(1 / 5) Stored
Injector Circuit / Open
- Cylinder 5

P0305(2 / 5) Stored
Cylinder 5 Misfire Detected

P0106(3 / 5) Stored
Manifold Absolute
Pressure/BARO Sensor
Range/Performance

P0205(4 / 5) Pending
Injector Circuit / Open
Cylinder

P0305(5 / 5) Pending
Cylinder 5 Misfire Detected


AFTER SWITCH/ CLEAR CODES:

P0205(1 / 4) Stored
Injector Circuit / Open - Cylinder

P0305(2 / 4) Stored
Cylinder 5 Misfire Detected

P0305(2 / 4) Stored
Cylinder 5 Misfire Detected

P0205(3 / 4) Pending
Injector Circuit / Open - Cylinder 5

P0305(4 / 4) Pending
Cylinder 5 Misfire Detected


So coils seem fine, I would assume the mechanic is right in assuming it’s an injector? I think I will still have him look at it tuesday I just don’t want to get hung with a crazy bill from the mechanic. I’ll be sure to have him call before he does anything, but if If it’s doable myself i’ll do it or at least order an injector so i don’t get taxed in parts, although he said he had some. Any suggestions? Im not a mechanic obviously, the valve cover job already seems like a PITA although i can do it, I don’t want to mess up my engine though messing with the injectors considering how deep they are.