So far I really like my 87.... but I have some concerns

[chevymotocross]

I really like my 87 silverado 2wd swb. I've had it for about a month now, and it's a big improvement over the 78 f150 I had. The truck seems to run really good and gets 15 mpg consistently, which is outstanding compared to the 9mpg I was getting with the ford. I notice whenever on the highway, after about 20 min of steady driving, the service engine light comes on. It never comes on during city driving, and all my fluids are fine, no overheating or abnormal running conditions that would hint me to pull over and get a tow truck. Many have told me it could be a faulty EGR.... but is there any other way to tell? Also, overdrive is great. I can cruise at low rpm and the truck is good on fuel. Problem is, when the truck is empty, on slight uphills, the thing loses speed quickly, downshifts, does it alot. When just towing my dirtbike on an open 5x8 trailer, forget it, the thing does not want to stay in od. It's only a 305, I know it's not a powerhorse, but it really seems to run out of steam on the highway on uphills.... I'm guessing it has a very high gear ratio like a 3.08, that could be a reason but is there anything I can do to give it some more pep on the highway? It has dual exhaust manifolds back with brand new cats.

[Ivan D.]

You know, my SEFI 5.0 has more power than most 305s, and it still does the exact same thing on long uphills, so I just throw it manually in 3rd and stay there till I'm about to hit the descent - I'd say don't worry about it, 3.08s are great for the long haul on level roads, but hilly areas in low rpms are not too pleasant with the OD. What happens if you keep the rpms a little higher, let's say above 2000? That seems to help for my car, and if you run stock-sized tires than we have damn near identical drivetrain ratios, so it should help you too. Another thing you may wanna look into is the TV adjustment - I ain't familiar with the 700R4 tranny (my truck has a 350), but with the Ford AOD the tighter the TV cable the longer the tranny keeps lower gears and the easier to drop out of OD - if Chevy overdrives follow the same logic maybe someone tightened up yer TV cable a little?

As for your check engine light - do you have a separate oil pressure gauge, or maybe a low oil pressure warning light? My truck has a gauge and no lights, but my experience with Ford products have been that if there ain't no gauge the low-pressure switch usually triggers the Check Engine light, way to go for manufacturing savings... the again my car don't have a gauge (or a check engine light for that matter), but it's got two oil warning lights - yellow one means add at least a quart, red means shut engine off immediately, pull over, and call for tow. On the other hand yer buddies may be right about the EGR malfunctioning...

I'm sorry for using so many Ford references on a Chevy site, but that's what I usually deal with, and the big three often use similar logic when tackling design issues.

[Captkaos]

Pull the touble codes from the ECM. Jump the top right 2 terminals on the ALDL connector and count the flashes. It will start with 12, one flash followed by two flashes. you can look them up on troublecodes.com or post them here.
As for towing, generally it is best to not tow in OD with a 700R4. It probably has 2,76 gears. You can probably move up to 3.42s to help towing...