My 89 420SEL is idling VERY roughly, and a local mechanic said my injectors need to be cleaned.

Can anyone tell me if this is a job I can tackle at home?

 

Did you already eliminate things like idle control valve, computer, OVP relay, ect........?

 

How many miles? If over 150,000 replacement may be in order – but I think you just need to replace the injector seals or look for a vacuum leak.

 

No, I haven't eliminated much of anything else. I replaced the heads about 1.5 years ago after a timing chain failure... so I'm thinking that the seals are probably okay.

Stupid question but how do I eliminate things like the idle control valve or the computer... that has to be done in a shop, right?

 

Not necessarily, the OVP has a fuse that can be checked; if the OVP is bad you may have the ABS warning light on. A bad ECU is possible but not likely – you can try soaking the ICV in carb cleaner for 24 to 48 hours to see if that helps – I still think it’s seals or vacuum leak.