1991 idle/running problem

[yeahiknowshesugly]

I have a 1991 k1500, 4.3 tbi, manual tranny with about 200000 miles
had been running fine then all or the sudden while going down the highway lost power,
couldn't get over 1500 rpms out of it try to give it more gas and she would back fire and try to die, 1st thing I thought was a fuel problem so replaced the fuel filter, after that it wouldn't start at all, checked and no fuel, replaced the fuel pump relay, still no fuel, (this was 75 miles from home at night in a parking lot). replaced fuel pump with a delphi now had fuel but still wont start, checked spark, was intermittent, had the control in the distributor tested, showed bad so replaced, truck would idle for 5-6 seconds and die, checked for codes and didn't show any, have also replaced throttle position sensor, temp sensor and computer, finely had it running long enough to get a code 33,
replaced the map sensor and now will idle like crap but as soon as you try to give it any gas and it goes over 1500rpms it dies again. have tried spraying carb cleaner down the tbi and it will stay running, fuel pump is at 13 psi and looks to be spraying good out of both injectors.
Don't know what else to try HELP.

[j cAT]

remove the upstream O2 sensor leave hole open could be a restricted exhaust. the ICM is also a good item to replace this old.

[yeahiknowshesugly]

icm has already been tested bad and replaced, also pulled the egr valve to make sure it was closing and have exhaust coming out of the tail pipe

[j cAT]

Originally Posted by yeahiknowshesugly

icm has already been tested bad and replaced, also pulled the egr valve to make sure it was closing and have exhaust coming out of the tail pipe

if no exhaust comes out it will not run,, restricted it will run ,but like crap . no power..

ICM bad may mean a bad coil/plug wire issue. also bad distributor bearing/rotor wobble.

[rhandwor]

I would suspect a stretched timing chain. Rotate counter clockwise a couple of turns to TDC. Mark the rotor and rotate clockwise and post how many degrees before the rotor starts to move. Over 15 to 20 degrees replace the timing chain.