This is bizzare...and its causing damage.

The last month while driving on the highway i've notice a surge and rpm jump at a sustained 2200RPM. Then, on Saturday it happened again. This time I had back fires and tonnes of black and brown smoke out the tale pipe. I couldint get past 2000 rpm. If I stopped or kept below 2000 it was ok. This only seems to happen on the highway. I have no codes at all. I tried to duplicate the problem by warming up the engine from bombing around the local streets. Different RPM in the gears. (350 Auto) but nothing.

So last night I went for about a 30km drive to a friends at around 120 kph no problem. We left his place. I follwed is 4th gen back onto the highway. As we got on we both hammered them all the way up to 170 kph. Then all hell broke loose. My backfire and bogging along with huge smoke reappeared. Couldint get passed 2200 rpm. I pulled over and idled with no problem. This time it backfired so hard the exhaust gaskets blew. So i limped it home at 80 kph no problem. Tried getting it to a 100 kph at around 2000RPM. and it started to backfire again. Put it in idle. Reved it to about 3500 and let off. It backfired hard again. Got it home left it till now started it, and nows theres no problems. It revs perfect. But I know if it hits the highway for any length of time ill be exploding again.

What the hell is going on here?

 

Its a 350 with 700 r 4. I think I may have made it look like I have a TH350 trans. Sorry

 

Did you check out your coil? Possibly your coil is getting tired and dropping out when it gets HOT. What coil are you running?

 

Im running an ACCEL super coil.

 

Also check to make sure your MAF is clean. Did your troubles start after re-oiling your air filters? If so, you may have coated your MAF with oil. It will probably throw a code in a couple of days.