99 f350 SD 6.8L
I get a strong fuel smell, takes a few cranks to start, idles fine for a minute or two then will surge at idle mainly in gear, but slightly in park. While driving it surges and hiccups and if I floor then let go it will back fire.
I figure its running rich. So I replaced my maf, tps, iac, fuel filter, fuel pump, fuel injectors, finally it went away. About a year goes by and it starts to happen again so I Replace maf again and change plugs, no fix.
it's blowing blueish smoke out the exhaust, raw fuel smell etc.
can't read codes due to no communication on obd 2 connector. Yes the fuses are good. Just won't communicate use to be able to. Another weird thing that started last year, if i hit the brakes, my temp guage shoots to hot then i let go and it returns to normal. Any ideas? Starting to think pcm may be bad or something.

 

A poor ground connection can produce things like this. The object now is to find it.
Better thing to do is to remove any ground connection you can see, clean it and reinstall it.

 

So I should remove all the grounds under the hood such as the main one that connects to engine and so fourth?
Seems weird that it would be running rich due to a ground but I'm not an expert mechanic lol

 

Don't worry about being an expert, that is the guy we call in to share the blame !

I'm not sure it is running rich and the one way to check without some tools is to look at the spark plugs. If full of black soot, yes running rich, but rarely caused backfire.
Running lean can though.

Blue smoke usually is from oil getting into the combustion chamber either from faulty valve stem seals or through PCV system..

Anybody check the oxygen sensors? Need to find why can't communicate with scan tool.

 

Spark plugs when I changed them looked like this.
I smell the strong fuel smell from exhaust so I assume rich.
Haven't checked o2 sensors.
none of the spark plugs were blantly wet but one or 2 had a thin layer of wetness to it.
Scan tool should be nice. I use to be able to connect to it same truck and same code reader, all of the sudden no good. Works fine on all my other vehicles.