My 1999 GMC Suburban just started “catching” when accelerating uphill and going 50+ mph. Does not occur any other time. Any suggestions?
Not sure what you mean by “catching”. Does it sputter and seem to lose power? Many vehicles don’t accelerate well going uphill; they usually downshift the automatic transmission.
Please give us a better description of what actually happens.
That’s the only way I could think to describe it. It doesn’t sputter, just seems to stop accelerating for a fraction of a second, then accelerates, then stops, then starts. My Suburban has always accelerated well before now.
Sounds as if it is loosing engine power under load. Could be plugs or wires. Hard to tell without seeing it.
could also be a fuel filter.