Good evening folks..I have an 04 STX 4.6 with 125,000 kms on it...had some EGR problems or at least thats the codes that were coming up about 2 weeks ago. Due to my travel scedule i couldnt get the truck in until this week to have it fixed. All the signs pointed to EGR (spark knock under load, mileage loss, general not 100%) On the trip to the garage it seemed to be very underpowered. We changed the EGR assembly (which includes the TPGI i beleive its called) inspected the hoses and such and reassembled. Drove the truck back home and was working much better but still not the power it should have. Idles perfectly but come to a stop and there is definite vibration. Bottom end or starting from a dead stop is weak but try to pass a car on a hill and it doesnt gain at all. Plugs were changed at 100,000 kms. CEL has not come back on since we changed EGR but thats not saying it wont. Anybody have any ideas or suggestionsas this has become a money pit in the last few months and its killin me.....thanks in advance

 

how does the throttle respond? do you have an oil charged filter? what kind of plugs were used? and did you use dielectric grease inside each cop boot? and how about the fuel filter?

 

throttle seems to "respond" right away now thats not saying much happens. At idle there is a slight hesitation when you give it a shot of fuel. no do not have oil charged filter....always fram. plugs are motorcraft put in by dealer and yes dielectric grease was used in boots. im wondering if possibly the plug/s could have been fouled when the EGR was faulty. Almost seems like its down a cylinder. Fuel filter has never had anything done lately (changed about 40,000 kms ago) and never really related it to this problem.

 

if the fuel filter is getting clogged then it is a possibility. my friends 96 f350 with 460 had a clogged filter and it couldnt get out of its own way. we changed it and that thing is night and day. it would definately be the first thing i'd try.