[Skoal_Man]

Hey all you fellow Chevy guys, sorry for the long post, but I have two questions with a lot of background. Let me start from the beginning... I have a '97 K1500 with the V8 5.7L, two years ago it blew a head gasket so I took it down to the block, bored the cylinders over 30, ground the heads flat and did a total rebuild. I did put a few performance parts in while I was at it such as the electronic fuel injection spider, and a K&N cold air intake. It ran good for a while, still not the best, but good, back in the summer I reworked my exhaust with 2.5" tube, took the cats off, put fake O2 sensors in, headers, and a Flowmaster muffler, ran great and sounded good, and most recently, I replaced the factory distributor with an MDI HEI distributor, however, I've had an issue with cold starts from the very beginning, (I was hoping that all of the above would fix it, but it hasn't) when I first fire it up and try to go, it acts like it has no power and doesn't want to move, if I give it more gas, it backfires several times and still acts like it doesn't want to move, but then, about 30 seconds later it's like a switch flips and it takes right off and runs great from there on out. It also does it if I stop for a few minutes ie. to get gas, so the engine is still hot. I also have a new problem where it throws a code saying there's an issue with the Cam Sensor, however the Cam Sensor is built into the distributor so I can't imagine that being the real issue, but when I first start it up and still have it in park, it idols strange, oscillating between high idol and such a low idol it almost dies, but if I throttle it up to around 2.5K RPM's for a few seconds it idols smooth after that, also while driving down the road it's almost like it misses really hard when I let off the throttle or am in a high gear and begin going up a grade and gets a load on it. Any help would be awesome, sorry again for the long post... Skoal Man out.

 

[Cowboytrukr]

Welcome to the Forum.

What's your fuel pressure?
Did you replace your coolant temp sensor with the rebuild?
Also, did you use a scanning code reader to set your timing?

Sounds like a vacuum leak. Even possibly a stuck EGR.

 

[Shoal_Man]

I haven’t checked fuel pressure, I will look at that. I did replace the thermostat and used a scanner to set my timing. I wouldn’t be surprised if it was a vacuum leak or EGR, I haven’t looked into either of those, what’s the best way to find vacuum leaks and what would I be checking as far as the EGR goes?

 

[Cowboytrukr]

There are varied opinions about the way to check the vacuum. Some swear by using TBI cleaner or carb cleaner and spray all the hoses. Others say use an unlit propane torch. An idle increase will usually indicate something leaking and sucking in the cleaner or gas.

The more I think about it, yours is a linear operation EGR instead of a vacuum driven one, but it would be worth pulling it off to verify the gasket is in good condition.

 

[Shoal_Man]

I’ll have to try that, thank you! I just don’t understand why it keeps throwing a Cam Sensor code, I’ve cleared the codes several times and it keeps coming back, it also started throwing a MAF code but I cleaned my MAF, so that should be good.

 

[Cowboytrukr]

You've already considered this, but how's the connector to the MSD? Is there some incompatibility with the MSD and the computer? Sorry, just reaching at this point myself.

 

[Shoal_Man]

That’s a good thought, the MSD is an OEM, so I didn’t think it should have any problems.