Bad EGR valve?

[dirtk38]

Hello,
I am having some serious problems with my 1998 5.7L Tahoe. Recently I have been having issues when trying to crank it. Sometimes the starter hesitates for a second and then starts to crank, but sometimes the lights just flicker and the car makes that electrical stuttering noise kinda like when the battery is low. Other times it will turn over and the engine will start but die as soon as I let go of the key. I've had my battery and alternator checked and everything is fine. Sometimes this happens, sometimes it cranks up just fine.

Yesterday, a new, more serious problem started to arise. With the engine at idle speed, the brakes pedal became hard to push and the car was hard to stop, as if the engine wasnt running at all. The past week or so I had noticed the brakes felt a little funny, but I wasnt sure if I was just making that up in my head. Also, last night, the engine almost stalled on me while sitting at a long red light.

A guy at autozone told me today it might be my egr valve. All the local mechanics were closed (small college town) so I couldnt go anywhere to verify this. My plan is to take it in first thing Monday morning, but what do y'all think? The EGR valve seems pretty easy to replace, but seeing as it costs around $160 i want to make sure thats it before I do it. My doubts come from the the electrical symptoms that I described in the first paragraph. Perhaps my starter is going bad too? Anyway, this post is already way too long, my apologies and thanks for reading.

-Kurt

[GMMerlin]

Usually we do not see problems with the EGR on that engine.
First thing is the electrical system...check the positive wire for corrosion build up at the battery..this can cause what you are describing with your starting problem...also make sure that all your battery cables are tight (at both ends)

As far as the brakes go, check for vacum at the booster check valve.

[dirtk38]

Originally Posted by GMMerlin

Usually we do not see problems with the EGR on that engine.
First thing is the electrical system...check the positive wire for corrosion build up at the battery..this can cause what you are describing with your starting problem...also make sure that all your battery cables are tight (at both ends)

As far as the brakes go, check for vacum at the booster check valve.

I do not see any corrosion, but one possible problem is that when I ran a cable to the positive battery terminal for an amplifier, it "crowded" the screw-in battery post. I could barely get it to screw back in. Can I buy a longer post? This could very well be the problem because one day i tightened it alot and the problem seemed to go away for a while, but now its back and the post is still tight.

How do I go about checking for vacuum at that check valve? A pressure leak of some sort sounds very possible, because whenever I hold the brake pedal down at low speed or at a standstill, it makes a noise that sounds like pressure escaping. Its kinda the same sort of noise that the pedal normally makes while you are pushing it down (maybe thats not actually normal...).

Also, I might add that I recently had the car in the shop for some body work and a transmission replacement. Ive never had any of these problems until i got it back from the shop (about 2 weeks ago). Coincidence or could the transmission people have done something wrong?

Thanks again