I have a 1996 4.9L Inline 6. Thing runs like a clock when its cold or when hot on the highway. But after she warms up she 's sluggish off the start and idles really badly(had to drive with two feet last night). went to see the "experts" at autozone and I got codes p0172, p0305 and p0335. I was told I'm running rich, No. 5 is misfiring and I got a bad crankshaft sensor. Any suggestions?

 

Suggestion #1: Other than letting them PULL (but not INTERPRET) codes, stay out of the zone!

Suggestion #2: Now that you have the code numbers, buy a Haynes manual (PN 36058 w/light blue cover) & a cheap digital multimeter (DMM) and follow the procedure in Ch.5 Sec.5 on p.5-5. Also, find the procedure for testing the CPS & the HEGOs & do that. Then pull the red vacuum line off the FPR with the engine idling & inspect for gasoline.



Yours is inside the intake cage on the R side front of the engine.

 

Fix your misfire before anything else. Verify spark and fuel to that cylinder, check compression. It's the little things that kill.