Odd problem need a little help with diagnosis

[yarnkaps]

Hi all, my '88 gt has had a bit of lag for a while and I noticed also that while cruising at highway speeds (not pushing it) the car seems to want to engage the turbo at odd times and every once in a while the check engine light comes on.

When I let off the gas for a split second the light turns right off. It also seems that if I am pushing the car a bit everything is fine it's only when I try and drive at a reasonable pace that it malfunctions.

I don't have this issue while driving in town other than a slight lag sometimes with the turbo engaging.

Has anyone dealt with anything like this before? I checked for vacuum leaks and was unable to find any.

[jay]

Might be clogged cat.

[nickz]

Check your o2 sensor or the wiring to it as well

[crazycanadian]

Check your ecu grounds and power... try and see if it will blink the trouble code its setting..

[BFMRGTX]

Have you pulled the codes?