jnav

Hi, I've got a nissan navara d40 2011 plate. So have had turbo issues, have had my turbo replaced and all the sensors around it replaced. The engine light still comes on. Now to me it gets strange. The turbo occasionally works while the engine light is on and the truck drives a dream. Then will go to start again once been off for 5 mins back to 3k rev limit. When the light is off (after each time coming back from garage) it's almost in limp mode 3k rev limit no response when put foot down. It's been like this for 2months or more now. Have had turbo off again and sent back to supplier and all good. Replaced egr valve as well as all sensors involved with the turbo. They said the engine is badly clogged up. When the turbo actually works it chucks out black smoke when put foot down. Have also run a bottle of cataclean through it. This is what the mechanics have said. He's stumped completely stumped. I'm at my wits end with it. I'm going to get a second opinion but thought I'd see if anyone knows of anything similar. Thanks James