big probs please help

[dashiftyfella]

uhh lesse where to start?
1. car shakes terribley below 2000 rpm feels like a missfire but i changed to plugs wires fuel filter egr cat exhaust map sensor idle air sensor throttle positioning switch.

2. new exhaust is caked with sludge after only maybe 30 miles

3. you can smell it running rich orr should i say you can smell gas.

4. cat exploded and clogged the exhaust system

5. cat used to glow red. i gutted the cat

6. back fireing throught the throttlebody

any ideas

[chas]

sure sounds like a fuel/spark problem. your cat should never glow red (it does get hot, but shouldnt get that hot). dont know the year of your vehicle but you could have a bad coil or bad coil pack.

i also believe there are some resistance tests you can make on the coil packs. you would need to check haynes or chiltons -- dont know the values/procedure off the top of my head.

[dashiftyfella]

if it is a fuel spark prob can i just change to a msd 4 type of system and force the car to run how i want? i know some systems have a air fuel adjustment right? then throw in a air fuel guage? :( :( :( :( :(

[dashiftyfella]

if it is a fuel spark prob can i just change to a msd 4 type of system and force the car to run how i want? i know some systems have a air fuel adjustment right? then throw in a air fuel guage? :( :( :( :( :(

[chas]

i would first check to see if you have enough spark. your pcm should adjust the fuel going to the cylinders to prevent the rich condition (unless the o2 sensors are shot). however, if only some of the cylinders have a problem (like a bad coil pack) the pcm wont be able to adjust the air/fuel ratio to make up for this.

if you have good spark, i would go after fuel. check fuel pressure. check compression in the cylinders.