starting issues and BAD gas mileage

[chrisLB]

been a while... i recently bought a low milage one owner, lady driven 97 GTP.. its my 4th GTP so im very familiar with the car and have had a lot of experience working on them.. here's the problem.
after i brought the car i noticed the gas consumption was high so was gonna look into it as regular maintenance was done to this vehicle at the dealership throughout the 20 years she owned it.. but after a week or so i noticed a slight bucking while driving at low rpms then as time went on a slight rugh idle when the engine was warm.. couple days later and it would shutter while idling and almost stall from time to time and now for the last week its iffy about starting if the engine is warmed up.. i was almost 100% sure it was the crank sensor but the tac does show around 200 rpms while cranking over and no start... BUT here's the kicker.. last night it wouldn't start so a tapped the harmonic balancer around the sensor and it fired right up.. so no check engine light, no codes and it does show a jump on the RPMs with a crank/no start.. its got all the power and no hard shifting.. runs great other then the gas mileage and intermittent problems.. any ideas?

 

[FordMan77]

Crank sensors usually never throw a code. If you suspect it then swap it out. I'd also check the harness that goes to it. Could be a wiring issue.

Since it's new to you, I'd start with new plugs/wires, air filter and go from there. Clean the TB and MAF. Then check for vac leaks. Check the "T" under the snout of the S/C and make sure it's good as they like to crack and cause vac leaks. Could be the cause of the fuel consumption issue.