TL;DR
Would you get a 2003 SLE with visible rust down below and clunky front end, or a 2005 GXP with a bad engine but lower miles and cleaner carfax for $2k less.

Full Story
Hey guys, new member and long time fan of the Pontiac lineup but never got a chance to pick one up before GM shut it down. I'm now in the market for something fun to drive, came across a bonneville one day and it just looked so good I had to go find me one.
After a couple weeks of nationwide searching I've narrowed it down to these 2 cars:

• First car is 2003 SLE, black with tan interior, 146k miles. This car looks like it might have had some water damage though - there'* a moldy smell and rust in the spare wheel well, along with rust around the front seat tracks and the bottom of the engine. The engine was pretty smooth although it has a O2 sensor code (B1S2 low). There is also a popping noise in the front end, especially when turning the steering wheel while driving. I could feel it in the wheel and I'm hoping it'* a ball joint or tie rod. My worry is the rust and possible water damage. Carfax doesn't state it but I can tell just based on how much different the top end of the engine bay is compared to the bottom. Even the engine mount had rust, and there was some barnacle looking stuff on the driver side towards the back.
• 2nd one is a 2005 GXP, gray on gray with 30k less miles than the SLE. It'* also $2k less than the SLE because of a terrible misfire which the seller believes is a head gasket issue (low compression in 2 cylinders). Aside from that the car was super clean with a one-owner carfax. Everything works, I did drive it a bit and it felt pretty good but it was a pretty short ride so there may be other issues too. From my inspection nothing jumped out though. I really wanted to open it up and see how it handled at speed but the shuddering was just too much and I didn't want to get stranded with someone else'* car.

So these are the 2 options I'm looking at. Both cars were a good couple of hours drive away but they were the best I could find without travelling across the country. I'm leaning towards the GXP just because of the lower price and the overall condition. I figured the $2k difference could be enough to fix the engine and I'd have a GXP with lower miles for just about the same price. What I'm worried about is the Northstar engine. I see a lot of negative opinions on it. Mostly head gasket stuff, but it also seems that you have to pull the whole thing to do any major repairs, which sounds like it could get pretty expensive and eat up that $2k margin quickly.

The 3.8 on the other hand is considered bulletproof and seems like a much easier engine to work on. Maybe not a peppy as the V8 but there'* the aftermarket support and potential for tuning. I've never done it before but this seems like a good engine to start with.

So in you guy'* opinion, which one would be a better investment for a weekend fun car?

Thanks in advance!

So I was checking out a 2005 the other day and it had a P0300 code and another one for the fuel injector circuit but I forgot what the number was, but the engine was shuddering pretty bad. The guy said he did a compression test and 2 of the cylinders were at 70psi and the rest I think were around 120psi. I tried a combustion leak tester and the fluid was still blue after almost 10 minutes, the coolant also looked fine so it doesn't appear to be leaking into the cooling system. I wasn't able to check the compression myself but my suspicion is that a valve or seal might be bad. On the other hand, the injector code has me wondering if there'* more than that so I wanted to get some opinions before I decided on whether to get the car or not.

1. Any thoughts/ideas on what the problem could be?
2. If I do get the car should I try to find the issue and fix it or am I better off just swapping the engine?

The rest of the car is CLEAN and it looks so beautiful I'm willing to spend the money to get her running again but I would like to know what I'm getting into before taking the leap.

Thanks for the help, guys.

Have you rebuilt any engines? If not just swap with good used one.

I'd stay away from the rust car. Nothing but drama awaits in a car that is in such a condition that it appears it has been been partially submerged.

You are correct: The Northstar car will cost a bunch to repair unless you know of a resource for FREE experienced labor. By "experienced" I mean experienced with Northstar heavy repairs.

Big question here: If these are the only choices for your circumstances, do your circumstances allow for thousands of dollars of repairs?

That'* a good question. As I mentioned, the GXP saves me $2k to throw into repairs and potentially more if I can get the price reduced. Right now he'* asking $4000 but I'm hoping to get it down closer to $3000. As far as labor, my buddy has a shop that I was going to take it to but after reading about these engines I'm not sure I'd trust his mechanics to work on it. Plus he'* been jacking up his rates lately so I'm better off shopping around. So far I've found one other guy who'* willing to do a swap for $1000 labor. After reading a few threads on this forum though I think I'd try to find someone that'* good with N* - this guy has experience but I'm not sure how versed he is with this engine.

So in short, I think about $2-3k to spend on repairs for the N*. Assuming about $1k on a used engine, I'll be looking to get the swap done for somewhere under $1500 and hopefully have enough left over for whatever BS the safety inspection pulls out of their ***.

I'd be concerned that every used Northstar you get is also bad somehow. Once they have major issues it takes just the right kind of artist to make them right again.

Moved from the "Pontiac Bonneville > 2000-2005" forum to the "Pontiac" forum.

Merged this duplicate thread: https://www.gmforum.com/bonneville-g...misfire-314474

. . . into this thread.

Post #2 and Post #3 came from the other thread.