Hi, I'm getting confused information from the van itself and two garages I've taken it to...the injectors were replaced 18 months ago, a month ago it stuttered when going through 3rd into forth, fourth into fifth, STOP light flashed on then immediately off...I had it looked at, told it's driving fine, but when diagnosed the reading says injector no.1...but the van drives fine again to a degree and STOP light not come on, I feel it will if I get up to 60mph however, but reading injector issues, it's not misfiring, it's not leaking, no noises, starts great everytime...so i dont get it...I have bought a decent reviewed cleaner and additive to mix into the fuel tank...any input off you guys be greatly appreciated