Thread: Histitations and clicking tapping noise from engine at highway speeds ???

I have a 99 grand prix gtp and when im on the highway at about 60 and i go to give it gas the engine starts bucking and i hear like a clicking/tapping noise from the engine area. I was reading some post and maybe it could be a clogged cat? I thought it would be a transmission problem but im not sure. Has anyone else had this problem? thanks

gotta be a little more specific. do the symptoms happen when you're giving a lot of gas to get to 60 or a little gas?

Originally Posted by bps02gtp

gotta be a little more specific. do the symptoms happen when you're giving a lot of gas to get to 60 or a little gas?

It does it at full throttle so alot of gas.

Yeah at full throttle it very well could be a clogged cat. How many miles first of all?

Originally Posted by bps02gtp

Yeah at full throttle it very well could be a clogged cat. How many miles first of all?

I actually have a code in there for p0303. The car runs fine no misfire at regular driving though. I have 148,000 on it.

Change the plugs and wires yet?

Originally Posted by Rico

Change the plugs and wires yet?

I just bought the car but the guy i bought it from said he put new plugs and wire in it. The wires do look new. I looked a the freeze frame data and the misfire happens at 44 mph and at 4800 rpm. And the car runs fine just normal driving around the city no mifires.

What kind of plug wires are they? Are the coils stock?

those coils might still be ok but you might want to pop them off and take a look to see how they are. probably wouldnt hurt to replace the plugs on your own to make sure they're good. if the misfire only comes at WOT then it could be a lack in fuel pressure or a clogged cat. that would be my guess.

Make sure you use either stock Delco Irridiums, or a good copper plug. Do NOT use any Bosch or Platinum plug as the ignition system in these cars tears them up.