95GT problems after a tune -up

my friends 95 Gt has 80,000 miles on it he just got a tune up and the only modifications done to it were air box was removed timing adjusted to 14 and a K&N filter and the check engine light comes on any suggestions

It might be a good idea to disconnect the negative terminal from the battery to let the computer reset itself. This takes about 10 to 15 minutes to clear and then reconnect. Anytime you do a major tune up especially if it involves timing or you change the rate that air comes into the car it has a tendancy to confuse the computer. And the first thing it does is give you check engine lights. I don't know how many times I've gone round and round with this car for that same reason. After you reconnect put it on the road and drive it for about 15 minutes, this will give the computer time to adapt to the new information its recieving.

Check the wiring to the Mass Air Meter. If it became disconnected or damaged, that will send a signal to the check engine light. Also, try reseting the computer as mentioned by eillob. If that doesn't work, push back the timing to the factory 10* and reset the computer again.

i just looked under the hood and couldnt find anything wrong,,but i started it up let it idle for about 2min then drove it and everything was fine

I know guys that have driven around for years with the check engine light on. The only time mine has came on 02 sensors fixed it.

Remove the K&N and filter box.Check the filaments on the mass-air meter.See if they're covered in oil(from the K&N).This happens a ridiculous number of times at my shop;people put in a K&N expecting a HUGE hp increase,and end up with a Check Engine light and reduced performance.Turns out that any excess oil in the filter gets to coat the MAF filaments,insulating them and eliminating their signal transmission to the EEC.Clean it off with some thinner and a Q-tip and the problem should go away.If it doesn't,then look elsewhere,but the filter should be your first concern here.

Good advice vbrpete, but I really wouldn't use thinner. I would use either rubbing alcohol or electronic parts cleaner. Also be VERY careful not to damage the filaments, because there are extremely delicate.

Remove the K&N and filter box.Check the filaments on the mass-air meter.See if they're covered in oil(from the K&N).This happens a ridiculous number of times at my shop;people put in a K&N expecting a HUGE hp increase,and end up with a Check Engine light and reduced performance.Turns out that any excess oil in the filter gets to coat the MAF filaments,insulating them and eliminating their signal transmission to the EEC.Clean it off with some thinner and a Q-tip and the problem should go away.If it doesn't,then look elsewhere,but the filter should be your first concern here.


ill show this to him thank-you