i have a 90 model half ton 4x4 with a 350. it runs fine until it gets hot and then it starts spitting and sputtering. it starts to smell like gas really bad and if i kill it and start it back up it idles down to about 100 rpm and comes back up for a while then it idles fine but still pops. i dont have a clue what could be causing this and any help would be greatly appreciated!

 

Is there any code pope up on the screen? I think it may be Oxygen sensor reading lean.

 

Might be a coolant temp sensor(the 2 wire one by the t-stat)i would check the resistance when hot

212f 177 ohms
194f 241
176f 332
158f 467
140f 667
122f 973
113f 1188 ohms
104f 1459
95f 1802
86f 2238
77f 2796
68f 3520
59f 4450
50f 5670
41f 7280
32f 9420
23f 12300 ohms
14f 16180
5f 21450
-4f 28680

 

i just changed the oxygen sensor and it seems to be running better. hopefully that solved the problem. thanks for the help!