Low compression/misfire

[jake12tech]

Hey guys working on a 98 e300. Car has 395000 miles on it. Someone I know bought it off Craigslist and grossly overpaid for it considering I am not quite sure what’s wrong with it and if the engine is worn out losing compression which I doubt.

Brought it to me on a tow truck for me to look at it for him. It started up the first crank in 30 degree weather on the first glow cycle but it has a ROUGH idle. Like the engine rocks back and forth as if it’s misfiring, but it does shoot some white smoke out the exhaust with a “puff” sound. Not a whole lot of smoke like when you have a completely dead cylinder. Just enough to be noticeable.

However when you rev the engine to like 2 grand it smooths out doesn’t shake rock, or anything. Driving the car also it has VERY little power. Feels completely starved of fuel. Newer fuel filter.

So I know the step here would be to do a compression test, but I’m trying to save a friend of mine the money id charge to do that and then the price of parts to replace the injector o rings.

I don’t think it’s compression however because why would it go on the first crank dead cold start in 30 degrees? And if it was a dead cylinder it would not smooth out with revs.

Injectors are newer too as well. The PO said it was running quite well not long ago and this just started happening.