1991 infiniti q45 Gas needle problems

[b1ackdiam0nd]

I have a 1991 infiniti q45 and the gas needle dropped below E now it all started a few months ago when i had a keyless entry put on my car by pros. When he brought my car back out to me the gas needle was dropped below E i didnt have to say anything cause i was late for school but i had them look over there work and the clam they didnt touch anything that had to do with the fuel system. I changed the cluster 3 times and get the same thing. i can take the glass off the cluster and move the needle to F with my finger hoping it would work again but it slowly drops back down to E when i the car on. Could this be a relay problem or did they really cut a wrong cord or something when they where putting the keyless entry on should i take it off what should i do

ps i was thinking about removing that and getting a remote start/alarm put on by best buy what are your thoughts on that also please respond anyone!!!!