ManiacMagoo
Well-Known Member
I have a 92 GMC k1500 Suburban with 245k I bought not to long ago and shortly after started having issues running. It has a 350 TBI in it.
Problem 1:
It idles fine out of gear and runs fine driving until you let off the throttle then it falls flat on its face if you abruptly let off the throttle. Dropped tons of brake cleaner on it not finding a vacuum leak. Then it recovers after about 5 seconds and idles fine. Mainly only does it in gear when ever you let off the gas.
Problem 2:
Was a quart low on tranny fluid but it shifted kind of weird since I got it. It holds 1st till around 3-4k before letting it shift to 2nd then almost instantly jumps to 3rd with a hard shift. If you floor it WOT it down shifts revs up past 5k like it is slipping then after about 10 seconds shifts and goes.
For problem 1 here is what I have done already. I replaced the fuel filter and pump, TPS, MAP, EGR seonsor, plugs, cap rotor, rebuilt TB, fuel regulator, and temp sensor. After driving on a 300 mile trip it started throwing code 22 and 32. I replaced EGR sensor and code 32 left and replaced connector on the new tps and 22 left. It feels like the timing advance isnt working so I replaced the timing connector as well to make sure it had a good connection. Always throw code 12 but I was told that is normal. Now if I unplug the vacuum line to the egr sensor or map sensor it stops acting up. I took the HEI module in and had it t4ested and was told it is fine. Seems to mainly do it after it warms up. At this point I'm leaning at a crack in the egr track in the intake, bad HEI module after it waarms up, faulty new tps, or a bad distributor. At this point I hate the thing.
For problem 2 I replaced the fuild and filter nothing smelled burned and no suprises in the pan. So I put 1 bottle of Lucus in and still nothing so now I think this is more of an electrical issue caused by problem 1 or atleast Im hoping it is. I'm going to add a grounding strap to the tranny. The shift points are all over the place now.
So thanks in advance to anyone who might have an idea. Sick of tossing money into problems to not have anything cured.
Problem 1:
It idles fine out of gear and runs fine driving until you let off the throttle then it falls flat on its face if you abruptly let off the throttle. Dropped tons of brake cleaner on it not finding a vacuum leak. Then it recovers after about 5 seconds and idles fine. Mainly only does it in gear when ever you let off the gas.
Problem 2:
Was a quart low on tranny fluid but it shifted kind of weird since I got it. It holds 1st till around 3-4k before letting it shift to 2nd then almost instantly jumps to 3rd with a hard shift. If you floor it WOT it down shifts revs up past 5k like it is slipping then after about 10 seconds shifts and goes.
For problem 1 here is what I have done already. I replaced the fuel filter and pump, TPS, MAP, EGR seonsor, plugs, cap rotor, rebuilt TB, fuel regulator, and temp sensor. After driving on a 300 mile trip it started throwing code 22 and 32. I replaced EGR sensor and code 32 left and replaced connector on the new tps and 22 left. It feels like the timing advance isnt working so I replaced the timing connector as well to make sure it had a good connection. Always throw code 12 but I was told that is normal. Now if I unplug the vacuum line to the egr sensor or map sensor it stops acting up. I took the HEI module in and had it t4ested and was told it is fine. Seems to mainly do it after it warms up. At this point I'm leaning at a crack in the egr track in the intake, bad HEI module after it waarms up, faulty new tps, or a bad distributor. At this point I hate the thing.
For problem 2 I replaced the fuild and filter nothing smelled burned and no suprises in the pan. So I put 1 bottle of Lucus in and still nothing so now I think this is more of an electrical issue caused by problem 1 or atleast Im hoping it is. I'm going to add a grounding strap to the tranny. The shift points are all over the place now.
So thanks in advance to anyone who might have an idea. Sick of tossing money into problems to not have anything cured.