alright i just bought my 99 gsr 2 weeks ago and it was running great but this week ive noticed it getting slower and slower and when i let off the gas it loses speed quickly also i havent been getting the best gas mileage any ideas?

 

Run a compression/leakdown test.

 

200 to 205 on all cylinders and didnt even move on the leak down the car only has 80k on the motor

 

ur caliper is probably locking. check ur brakes or your emergency brake to see if its sticking

 

tried changing the plugs and someone suggested platinum iridiums so i tried those. the car would ilde fine but as soon as i touch the gas it would stall out til 2k. i had to floor it from idle just to get it past there but as soon as i put in the old plugs which are bright white and look like their junk and it runs fine but still slow

 

get rid of the iridium's. Turbo, NOS and very high compression engines benefit from these type of plugs. NGK platinum and make sure they are the correct temp range plugs.