I really need help
 

I have an 89 260E runs great untill i just put 6 new bosh platuim 2 spark plugs in now if u leave it on it will ildel but after a while it drop out and die then u would have to start it over and it will start with its usual one turn.
Can anyone give me some advice.

Stick with original plugs. Like original spelling, they work the best.

i dont
 

think the plugs are the problem, unless there is something wrong withthem.

ie wrong gap, broke poecelain while installing, loose or damaged plug wire. i would examine the plug wires carefully especially the connections to the plugs to see if you might have damaged one while r and r. then if that reveals nothing take the plugs out and look for cracked porc. and check gap.

when i had a 300e 2.6 i am sure i used platinum plugs with no prob.

tom w

I would take a good look around the engine to make sure that no electical connections or vacuum lines were knocked off when the plugs were being changed.

replace your plugs with the correct bosch plugs (H9DC or H 9 DCO depending on manufacture date) for $1.75 each and your problem will go away. Do a search on "spark plug and resistor" and you'll find information as to why the platinum plugs do not work well with Mercedes ignition systems. Other techs can comment about this as well..

Bosch Platinum plugs in Mercedes
 

It is simply NOT TRUE that Bosch platinums do not work well in Mercedes. It appears that a RESISTOR plug, whether regular copper or platinum, will not work well in most Mercedes. But, I have installed Bosch Platinums in several Mercedes with excellent results. Obviously, they were not resistor type plugs and I used both Bosch 2's and quad's in these cars, with good results. Why do certain people think the simple answer to every ignition problem is to eliminate the platinum plugs? It just is not true.

I am not going to say that a plat plug won't work in MB engines. I will only say some may and some may not. My 500SEL DOESN'T like the plat plugs at all. If I have learned anything in the last 50 or so years working in engines is "Always Use The Plugs Called For By The Manufacturer" as they will ALWAYS work. Others may or may not. I would recommend you but 6 plugs of the correct brand/type called for. If you still have problems, then fix the problem and try the plats again if you like. If your engine is one that doesn't like the plats (like my 500) then the plugs will fix the problem. If you leave the plats in and try to fix the problem you may spend great amounts of money and never fix it.
A rule in my shop, I will not work on drivablilty problems unless the car has the exact plug called for by the manufacturer. If the customer has put in something else (or has had it done) and won't let me put in the correct plug I will just send him on his way. I would much rather him tell others that I wouldn't work on his car because it didn't have the type of plugs I like than either not make any money because of the time it takes to trouble shoot this type of problem or charge him for my time and get the reputation that I rip people off.

It ran great.
You changed plugs.
It now does not run great.
What would you suspect first?

As other have advised, I advise you to first go back to the plugs that did not give you the problem.

If the problem persists, you may then conclude that it is not the plugs and another problem was created when you changed the plugs...

Best Regards,
Jim