Slight miss at 1800rpm

Hey guys, I have a td42 silver top, now it has a very slight miss/shudder that starts at 1800rpm , also engine has no Blowby. Iv flushed the tank, blew the lines and put fresh diesel in her, I noticed when I changed the fuel filter there was tiny bits of shit in fuel (fragments from old fuel hose I think). So I put new hoses on ect, also it didn't have a gauze , so Iv put a new guaZe in it. I'm wondering if it Could be shitty injectors due the fragments in the filter? It's an old 10mm pump, so Iv ordered a lift pump also to see if that will help it by holding fuel pressure. Any other segestions? Cheers.

Do you get a puff of white smoke when it happens...my td42 doesnt burn oil but when it misses like this it pops a white cloud out the zorst...me old man recons its fuel n could be a leaky injector of sticky valve.

Nah mate , no smoke. It's weird, you can hold it on 1800rpm and it will miss/shudder ect and then 2000rpm it will be perfect , then 2200rpm it will miss/shudder again and so forth, but it doesn't happen untill 1800rpm. It's doing my head in.

what do you mean by blowby , - blowby is crankcase gasses venting out of the rocker cover and returning thru a hose to the inlet system . you will always have some noticeable blowby if you pull the hose off . so i am thinking you mean something else by blowby ? i think it might be a good idea to check the gauze again as any residule rubbish in the fuel lines might have partially blocked it . and it would not take much to do so . perhaps use some fuel injector cleaner and/or 2 stroke oil in the fuel .

Yes crank case blowby, it doesn't have excess blowby. reason I mentioned this is because on Facebook there were people saying slightly bent rod, cracked Pistons ect. I checked the guaZe again and it had a tiny bit of gunk, cleaned it and it's still got it. Iv just noticed the primer goes soft when the car is running , you can pump it half a dozen times before it goes hard again?

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Originally Posted by Waadles

Yes crank case blowby, it doesn't have excess blowby. reason I mentioned this is because on Facebook there were people saying slightly bent rod, cracked Pistons ect. I checked the guaZe again and it had a tiny bit of gunk, cleaned it and it's still got it. Iv just noticed the primer goes soft when the car is running , you can pump it half a dozen times before it goes hard again?

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Does the car hit 'n miss while you're pumping the primer?
Possibly leaking air into diesel lines somewhere??

Nah it doesn't, doesn't miss a beat on idle not up to 1800rpm. If it was getting air wouldn't it puff out white smoke as the miss happens? Or not necessarily ?. I'm putting new lines and a lift pump on it this week. See how that goes

drive it like Mario Andretti for a while and see if that unsticks that valve you thought it might be
Anything unusual happen recently that you can think of

so far i would be inclined to go for some injector cleaner or possibly even some 2 stroke oil as i think it is sounding more like an injector issue . the primer being soft when running i think is normal as fuel is constantly being sucked thru it . i think it could be a sticky valve issue but i think you would hear that . fitting a lift pump might confuse or disguise the problem , so i would hold off on that until the problem i found and sorted .

Can you detect any wear or flat /sticky spots in your accelerator cable/linkages or slop in the pedal at 1800rpm ?