I get this occasional rumbling lasting 5-10 seconds, not very often, when I'm going around 20mph then resumes to normal. Last time it happened I punched the gas, the rpms didn't increase and it felt as if there was an issue the air/fuel ratio like it was struggling lasting only a few seconds. I have already cleaned the MAF sensor and TB, checked plugs, replaced air filter, computer is not throwing any codes. Any ideas? I'm thinking of replacing the fuel filter.

Also sometimes when I go from reverse to drive the rpms drop to 300-400 and feels like its going to stall just for a second.

 

Id definitely would change that filter how many miles do you have on it

 

Unknown. Best guess is 260000. Odometer doesn't reflect actual mileage.

 

I just changed the fuel filter with no difference noticed. It still occasionally runs rough at idle but only while in second gear like coasting through a turn or in a parking lot.

I'm planning on checking the resistance through the ignition system wires. Any ideas about what could be causing the trouble?