I recently bought this car for 2K with 130K mile on it the previous owner used regular gas and gave him problems on hessitating to run smoothly upon starting but after while it runs very smooth until the car slows down again. Now I just put a full tank of premium gas with some over-the-counter additive to boost octane..now the car runs a lot better only at the beginning it will back fire then it pick up the speed and run smoothly. Does anybody has the same or similar problem? PLEASE give a piece of advice what do I need to replace to make this very NICE car runs smoothly again on the road.

Thanks,
JR

 

Assuming it has fuel injection, the injectors are probably in poor shape with deposits and/or need service. I use Techron to keep my injectors clean on all my rigs. I have a V-10 gas work tuck with some substantial mileage on it now and Techron keeps the injectors clean. If not used at least once a month, I can see the mileage drop off.

I'd stay with premium gas, but instead of the "additives" to boost octane, I'd go with a proven injector cleaner. You've got nothing to lose but a couple of bucks. However, it's possible that his yrs of cheap gas have damaged the injectors and maybe even other fuel delivery parts.
Kevin

 

Just put in premium fuel and a can of seafoam injector cleaner,then go get the proper plugs for the m104 bosch F8DC0 and the connectors from .autohausaz.com and change the plugs.
If he neglected it ,it is also time to change oil and filter and probably all the other fluids.
ohlord
do not use platinum plugs in the m104 engine the copper oem plugs are hat that engine loves.

 

THANKS a LOT Guys for your response. I did use premium gas since i bought the car and there's a little hessitation especially when I slow down to 1500 RPM. I just have to release the gas pedal then hammer it again to get ride of the back firing..Is that OK to do? I haven't change the plugs yet I will definitely do it this weekend also change the oil since I have synthetic oil to spare.

Ohlord, is it ok to use LUCAS brand for injector cleaner or the BG44..please advice.

Thanks,
JR