# Pontiac Grand Prix code P0304 misfire **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** pontiac, lights, engines\ **Created:** [April 8, 2022, 5:45am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471 "2022-04-08T05:45:13Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Angelv3059\_180292](https://avatars.discourse-cdn.com/v4/letter/a/e9bcb4/32.png) [@Angelv3059\_180292](https://community.cartalk.com/u/Angelv3059_180292)\ **Post date:** [April 9, 2022, 2:31pm UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/21 "2022-04-09T14:31:23Z")
Hello, sorry yes all of the other cylinders were within normal pressure range over 100. Thermostat was not causing any issues with overheating ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [April 9, 2022, 4:13pm UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/22 "2022-04-09T16:13:33Z")
Buick 3800. Solid motor. Fix it. 07 had 3800 or 5.3. I think you would have mentioned it had a v8. ---
**Author:** ![Angelv3059\_180292](https://avatars.discourse-cdn.com/v4/letter/a/e9bcb4/32.png) [@Angelv3059\_180292](https://community.cartalk.com/u/Angelv3059_180292)\ **Post date:** [April 9, 2022, 4:47pm UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/23 "2022-04-09T16:47:27Z")
Yeah I apologize Pontiac Grand Prix 07 V6 3.8 L no supercharge. Most likely bad valves, is it worth replacing with a used engine w low miles or fix the engine in my car now that has 177k+ miles. Thank you for feedback @Cavell ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [April 9, 2022, 6:23pm UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/24 "2022-04-09T18:23:12Z")
Everyone sees replies. No need to name names. Can you do the work? Or will pay a shop to do it? ---
**Author:** ![Angelv3059\_180292](https://avatars.discourse-cdn.com/v4/letter/a/e9bcb4/32.png) [@Angelv3059\_180292](https://community.cartalk.com/u/Angelv3059_180292)\ **Post date:** [April 9, 2022, 6:27pm UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/25 "2022-04-09T18:27:08Z")
I apologize! Unfortunately no I can’t do the work. A shop was gonna charge me 2200 to put the engine in. The engine I could get for $600 with 70k miles on it apparently. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [April 9, 2022, 6:51pm UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/26 "2022-04-09T18:51:25Z")
That is cheap, what is the reason for the indecision? Do you not trust their work? Would you rather have a new car? ---
**Author:** ![Angelv3059\_180292](https://avatars.discourse-cdn.com/v4/letter/a/e9bcb4/32.png) [@Angelv3059\_180292](https://community.cartalk.com/u/Angelv3059_180292)\ **Post date:** [April 9, 2022, 7:08pm UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/27 "2022-04-09T19:08:06Z")
I’m indecisive because I’m worried about the complications I can have putting another engine in my car but I don’t know anything about cars! I just want what others think would be the best idea to do…either way it’s pricey ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [April 9, 2022, 7:15pm UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/28 "2022-04-09T19:15:24Z")
Have the shop perform a leak-down test. The low compression on cylinder #4 could be caused by a broken valve spring. ![image](https://global.discourse-cdn.com/cartalk/original/3X/f/8/f8313ca5b4ef95fec0a6a1e82c95d5b6cc1e88b7.jpeg) Tester ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [April 9, 2022, 11:24pm UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/29 "2022-04-09T23:24:08Z")
> [@Angelv3059\_180292](#): > > the other cylinders were within normal pressure range over 100 Normal cylinder compression pressures tend to be in the 160 to 180 psi range. ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [April 10, 2022, 12:16am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/30 "2022-04-10T00:16:15Z")
> [@Angelv3059\_180292](#): > > I’m indecisive because I’m worried about the complications I can have putting another engine in my car If putting a used engine in your car is going to make you lose sleep then don’t do it. Check on a rebuilt with some kind of warranty or even a new GM crate engine. You are going have more money in this thing then it is worth and what if in 3 months from now you need a transmission ? How will you feel then ? ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [April 10, 2022, 12:56am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/31 "2022-04-10T00:56:57Z")
An engine like this in great condition should have cylinder pressure readings nearing 200. If you are saying that the cylinders other than the 60 PSI one are in the 100 PSI range then the engine is done. Compression ratio is roughly 9.5 to 1. Normal, good compression means 20 X that C.R.; ergo 190. Even with wear one would prefer the 175 range. ---
**Author:** ![neburex](https://avatars.discourse-cdn.com/v4/letter/n/e95f7d/32.png) [@neburex](https://community.cartalk.com/u/neburex)\ **Post date:** [April 10, 2022, 1:17am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/32 "2022-04-10T01:17:57Z")
> [@Angelv3059\_180292](#): > > Yeah I apologize Pontiac Grand Prix 07 V6 3.8 L no supercharge. Most likely bad valves, is it worth replacing with a used engine w low miles or fix the engine in my car now that has 177k+ miles. Thank you for feedback I just got rid of an 02Camry. In twenty years all I put in it was a water pump. Then it started, struts, starter, evaporative sys corrosion from twenty metal eating winters, throttle body that’s acting up, front wheel bearing probably, tires soon, registration renewal, trans so so, 20mpg city 26 hwy and so on. I had a dispatcher who paid more for gas to commute with his DeVille than the car payments for a new car. You don’t know about cars, used engines can be a crap shoot, and do you really need a 15yr old gas hog. You feel attached??? Put a ring on your finger never through your nose. ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [April 10, 2022, 1:22am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/33 "2022-04-10T01:22:28Z")
> [@neburex](#): > > do you really need a 15yr old gas hog With a rating of 20 city and 30 highway I don’t think Gas Hog applies . ---
**Author:** ![neburex](https://avatars.discourse-cdn.com/v4/letter/n/e95f7d/32.png) [@neburex](https://community.cartalk.com/u/neburex)\ **Post date:** [April 10, 2022, 1:26am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/34 "2022-04-10T01:26:58Z")
Yeh, it do. Mazda 6 for instance. I have Niro between 50 to 60mpg. We charge our EV for free and since I’m retired I haven’t put gas(13 gal I think, it’s been awhile)in the hybrid since Dec 31st, 21. Op never mentioned or I missed it, where he’s from. Desert, coast east or west, mountains, may have some to do about wear and tear on engine and all else. What he needs it for may be relevant I think. Commute 5mi or 50, a putt around the block with the old lady, is he 25, 50 or 75yrs old. I’m just sayin. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [April 10, 2022, 1:56am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/35 "2022-04-10T01:56:09Z")
> [@neburex](#): > > We charge our EV for free Well somebody pays. Maybe not you but somebody. Not much except air is truly free. But don’t park that thing in the garage in case of fire. Houses are definitely not free. Yeah I’m retired too but I’m concerned the stuff I don’t pay for today, my grandkids will have to. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [April 10, 2022, 2:12am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/36 "2022-04-10T02:12:07Z")
MSRP on those two KIAs starts at $70,000 combined. If I were that loose with money, I would fix the Pontiac just for fun. ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [April 10, 2022, 2:29am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/37 "2022-04-10T02:29:29Z")
In this crazy market, I’d rather fix what I’ve got, versus buy ANY car . . . new or used ---
**Author:** ![Angelv3059\_180292](https://avatars.discourse-cdn.com/v4/letter/a/e9bcb4/32.png) [@Angelv3059\_180292](https://community.cartalk.com/u/Angelv3059_180292)\ **Post date:** [April 10, 2022, 3:04am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/39 "2022-04-10T03:04:29Z")
I have replaced my transmission in this car over 2 years ago and it also had low mileage on it. When I bought the car the dealer failed to notify us that it was having transmission issues so I hope the transmission is fine for awhile now. Do junk yard engines come with warranties usually ? Rebuilt and manufactured engines are expensive as heck compared to used ---
**Author:** ![neburex](https://avatars.discourse-cdn.com/v4/letter/n/e95f7d/32.png) [@neburex](https://community.cartalk.com/u/neburex)\ **Post date:** [April 10, 2022, 3:06am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/40 "2022-04-10T03:06:12Z")
The monroneys’ were actually closer to 80k. You could get a plain Niro for about 25k at least back in late 21. I live in an apt.now. I had a house with garage where I could work on cars. The OP acknowledges little knowledge of cars. It’s tough enough for knowledgeable people and you know you may spend thousands on what turns out to be a turd of an engine and than what? Nobody’s asking him what his situation is. All the pertinent details that relate to him, not how much joy and satisfaction it gives us to go to Joe’s garage and dicker over a price for something he knows next to nothing about. He needs transportation not a knuckle busting hobby. ---
**Author:** ![JoeMario](https://avatars.discourse-cdn.com/v4/letter/j/3bc359/32.png) [@JoeMario](https://community.cartalk.com/u/JoeMario)\ **Post date:** [April 10, 2022, 11:02am UTC](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471/41 "2022-04-10T11:02:06Z")
@Angelv3059_180292: > Hello, sorry yes all of the other cylinders were within normal pressure range over 100. Do you have the exact readings from those other three cylinders? Having those would be useful for us to help you. As others have noted, performing a leak-down test is the next step needed to be able to make any informed decision. [Previous page](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471.md?page=1) [Next page](https://community.cartalk.com/t/pontiac-grand-prix-code-p0304-misfire/183471.md?page=3)