After dash gauge showed lower than normal readings (<20psi @2500rpm) figured this could be a big problem .Fortunately after checking with mechanical gauge the normal readings were seen(40psi).When the ignition is in the on position the dash gauge reads 0 and when the lead is grounded the needle is pegged.Before spending $35 on a new sending unit,can someone tell me if the problem is in the unit or the dash gauge. Is there a way to check the sending unit such as with an ohmeter. Thanks for any info. It's on a 1995 3.0L Merc without the optional alarm system
