97 GTP hesitation/sluggish acceleration...HELP ME PLEASE!

[n8rade94]

I have a stock (to my knowledge) 97 GTP with 227k miles that I just bought a few days ago. The car idles decent, drives alright but wheni hit the pedal hard I get a hesitant or sluggish response, it also seems to be worse if A/C is on (could be my imagination). Just yesterday the car was bogging down real bad while idling and driving (putting noise and feel), service engine light was blinking so I knew something was seriously wrong. Today (6-29-17) I replaced all the spark plugs and wires, plugs are ACDelco Iridium PN# 41-101 and a Duralast wireset PN# 4690 . After replacement was finished i started up the vehicle and to my relief it idles a lot better, maybe not 100% but a heck of a lot better than the previous day. When I went to drive it, it also seemed to accelerate quite a bit better but still has some hesitation. Check engine is no longer blinking but still present. Have not had time to run codes yet but will tomorrow morning. I also have a brand new fuel filter I plan on replacing tonight. If anyone has ideas on further steps I can take to help my car run and drive as good as it can i would be extremely happy to hear them out and possibly try them out. I don't want to add performance parts until i know the motor can handle it (unless someone thinks differently). I do know the car has high mileage and seen its prime but would still like to make it perform as best as possible. I am no mechanic by any means but want to start working on my own vehicles as best as i can A.K.A self taught by my good pale "YouTube".

P.S. **I ran the codes before the service engine light began blinking and the only code that showed up was P1652 - Fan 2 relay control circuit. Did not think much of it because im not sure what that means so if anyone knows if the could affect the performance please let me know or what it even is or means. Thanks for reading hopefully I hear from some of y'all soon!**

 

[codyswanson4]

If your CEL is blinking, I believe that always means the car is misfiring. There should be at least a stored misfire code in the computer (I believe? How did you read the codes?)...now diagnosing that is another issue. Check for spark on all your plugs, did the misfiring only happen after you replaced the plugs? Ignition issues are the easiest to fix and rule out. Also, how did the old plugs look?

 

[blueguy91]

Most likely needs a full tune-up is needed. I'd say check all the vacuum lines (if you have a live feed scanner read the fuel trims; if they're pegging at 16.4, you've got a vacuum leak). They're more than likely dry-rotted; common issue. Could also be the intake gaskets (if they've been on the car quite some time they'll need replaced and are usually the main killer of these cars). Is it just a P0300 random misfire code? If so...that would make me lean towards a vac leak or a clogged cat if it gets slower or hesitates more as you get into the pedal, more.