I have a 91 Silverado with 5.7 TBI. When I start the truck cold the idle is low/fluctuates until it warms up in After about a minute of warming up it runs fine. I get a little bit of a lope every now at then at idle but other than that it idles and runs fine after warming up. This has been going for 2 months. I've seen a lot of possible solutions including EGR valve, temp sensor, TC sensor etc but have not tried to replace anything yet. Any thoughts? Thanks.