KTGS300

Spark plugs on my 2002 GS300 were due for a replacement. I replaced all plugs with NGK iridium plugs with new NGK plug wire set and now my car hesitates when taking off from a stop. There is no CEL code. It runs fine when cold but once the engine warms up that's when the hesitation problem shows up. Any ideas what could be causing this issue? Do I have bad plugs or wire set? What else can I check for?

[UPDATE]
I think we have solved the hesitation issue during take off. After reading a post by TW99GS300 on another thread about the coil wire position, I went back to check mine since I replaced the coil connectors. Sure enough one of the connectors was different from the other two. I must've messed it up when I put that one back together while replacing the connector. Took the car for a nice 30 minute ride and no more hesitation! Crossing fingers that was it.

TW99GS300

I would check the coil pack harness. you may start getting misfire codes soon if that's the issue.

KTGS300

I inspected the wiring to the coil pack when I replaced the connectors, no visible damage to the wires. It's weird that it only happens after the engine is warmed up enough after a few minutes of driving. When starting from cold, it takes off normally without hesitation. I also replaced all the hoses (ventilation and vacuum) that goes to the throttle body and air intake. It is driving me nuts because the car has not thrown any CEL code and I have been driving it for a week now.

Mr Jokster

iTrader: (8)

Did you check your gaps? Yea, they usually come pregapped, but they can still come messed up.

KTGS300

No, I didn't check the gaps. Could that be causing the hesitation, if the gap is off? Really not looking forward to taking everything off again to check on the spark plugs.

BayAreaLex

If this started immediately after you swapped plugs, then most likely:

a.) one of the spark plugs may be faulty or gapped wrong.

b.) loose connection between plug and coil

If a coil went bad, you will usually get a CEL pretty quickly.

Good luck