1998 slt z71
Newbie
I have a 98 GMC 5.7 L vortec and she's not running very well. When idling it does some minor hitching sometimes it doesn't. Putin around up to about 75-80 km/hr it's not to bad but when she goes into overdrive especially on the highway she hitches pretty bad. Put new plugs and wires in about 4 years ago (4000 kms) and did cap and coil about 4 months ago. Any ideas?
