ctafoya Report post Posted August 10, 2021 My kids 96 1500 is sick. Throwing a p0300 random misfire code. Fuel pressure is 60 PSI. Plugs look like it's running lean. It has 215k miles so I'll probably replace them, wires and cap. PCV is good and I have good vacuum. Sprayed carb cleaner everywhere and couldn't find any leaks. Any other ideas before I pull the intake and replace the spider assembly? Share this post Link to post Share on other sites
Saguaro Report post Posted August 10, 2021 Not sure I can help with that. I would be curious what the compression is. Do you check that when the plugs are out? Share this post Link to post Share on other sites
Edge Report post Posted August 10, 2021 Crank/cam sensor? Share this post Link to post Share on other sites
arizonian Report post Posted August 10, 2021 Check compression and connections at the coil(s) and at the injector(s) and look for corrosion (green crusties). I have used two bottles of Techron in a quarter tank of gas to help clean out the injector(s) and have had the money light go out. Doesn't work all the time, tho. Can you see the short term and long term fuel trims? Share this post Link to post Share on other sites
dse Report post Posted August 10, 2021 Check the ignition module. Share this post Link to post Share on other sites
Beaton Report post Posted August 10, 2021 Your on the right track. Might sound dumb but I had a 98 with a 5.7. Did the same thing. Mine had a factory external fuel pump in front of the tank on the steel fuel lines. Mine was plugged did a tune up and all kinds of stuff. Took that filter out and it was completely plugged which caused the lean condition and the light went out and ran great after filter was changed and my code was p0300 which is a multi misfire. 1 Share this post Link to post Share on other sites
Beaton Report post Posted August 10, 2021 Not fuel pump fuel filter. Sorry Share this post Link to post Share on other sites
muley224 Report post Posted August 10, 2021 I wouldn't throw any money at it until you run a compression test on all cylinders. Share this post Link to post Share on other sites
ctafoya Report post Posted August 10, 2021 I'll run a compression check and get back with results. I'm assuming I can just pull the wires to fire the coil and fuel pump relay. It's been a while since I had to wrench on anything. Share this post Link to post Share on other sites
Sky Island junkie Report post Posted August 10, 2021 Air flow sensor can make them act batty Share this post Link to post Share on other sites
360 0r Better Report post Posted August 11, 2021 What engine 4.3 5.0 or 5.7? P0300 could be any number of things but most common is spark plugs, fuel filter dirty air flow sensor dirty. Share this post Link to post Share on other sites
ctafoya Report post Posted August 11, 2021 Well I quit being lazy and removed the airbox and pulled the plugs on the even side. 2 and 8 are oil fouled bad 4 and 6 are on thier way. Getting ready to test compression........ Share this post Link to post Share on other sites
ctafoya Report post Posted August 11, 2021 Compression is good. 1, 2, 7, and 8 are 195. 3, 4, 5, and 6 are 190. I think the gauge reads a little high. 1 Share this post Link to post Share on other sites
Crazymonkey Report post Posted August 11, 2021 Compression is good .with high mileage I'd figure your valve seals are getting a little weak and your running a bit of oil down thru .sounds like new plugs and see what happens Share this post Link to post Share on other sites
deerhunter Report post Posted August 11, 2021 I had the same issue. Changed out the plugs and fault was still there, changed out the wires, still there. Ended up being a bad wire coming off the alternator. Keep in mind some faults will be pointing to the most obvious when it’s actually another issue up stream or down stream. Just don’t want you to throw a lot of money at your ride if you don’t have too. Electrical issues are a nightmare!!! Especially on the newer CAT and PACCAR engines 1 Share this post Link to post Share on other sites
