96 Ram 1500 Misfire Gremlin

[DanKScott]

Hello, I have been chasing a misfire issue for the better part of a year now and have no idea whats going on. I have a 96 1500 with the gas 360 in it. I have replaced plugs, wires, cap, rotor, injectors and ive even went in and done timing chain and sprockets. Done compression tests lowest I had was 115 which from all my research is perfectly fine. Biggest annoyance is the fact that I have no actual check engine light on about it. You can see and feel the entire truck jump at idle when it misfires. Then it gets pretty bad at about 35-40. Im just at a loss. I know theres a bunch of vacuum lines as well i just dont know where to start with that. Any help would be greatly appreciated. Thanks, Dan

 

[Green_Manalishi]

Only thing I can think of is the intake plenum gasket can cause a misfire, or you could have a cracked head. They were bad about that. Thankfully, my 1996 360 has never been apart and runs fine after 200k.

 

[Jocephus86]

Take a look at this option for a DIY smoke generator. I've built one and used on multiple vehicles.

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In this video we build the best smoke tester (IMO) for finding vacuum leaks! LINK TO WIRE LEADS https://amzn.to/2CJRgd5LINK TO WICK https://amzn.to/2pSreMfLI...

youtu.be

 

[Yeret]

Definitely suspect the plenum gasket. I've been down that road before, replaced all ignition components, checked fuel pressure, cylinder pressure, nothing fixed the problem.

Like you, my truck also used to shake horrendously at 40 MPH, which was when the overdrive would kick in. It got so bad I had to just turn it off until I got to around 60, then turn it back on, at which point the spark knock would enter the chat if I wasn't reeeal light on the accelerator.

Had plenum gasket replaced with the Hughes kit along with new heads because the old ones were pretty cracked up. Problem solved!