Help....... Ive been tryin to track down the cause of this....my 99 blazer fires right up idles fine problem is when i put it in drive and press the gas its normal until it hits 2000 rpms then it drops down to 500 doesnt stall it sdoea this a couple times i have to stay on the gas to keep it going once it passes 2000 then it goes. Any suggestions or help pointing me in the right direction would be awesome.........

 

Check fuel pressure and leakdown first. This link will help: https://blazerforum.com/forum/2nd-ge...eakdown-88305/ Post all 4 readings, and we can analyze them.


If it checks out OK, next step is check exhaust for restriction, (possibly a restricted catalytic converter).


Is the check engine light illuminated? If so, what codes are in memory?

 

The fuel pump had recently went out.. so intead of paying the $250 from autozone for an ac delco i found one on amazon (prime choice) is the brand name, i knew i was taking a big chance but i needed my blazer running. It has been very reliable. So with your mentioning fuel pump reminds me that it acted this way right before the other fuel pump went out. The engine light is on..awesome gas attendents at gas station did not put cap on completely. I recently ordered a scanner so i can get any codes to find out wat is going on. I dont believe my cat is clogged it is something i will check. Thank you for repling soon as my scanner gets here i will pull the codes and post them....

 

While you are waiting for a scanner, let me ask if you replaced the fuel filter when you replaced the fuel pump? You may have gotten a bad tank of gas and it partially clogged the fuel filter, so that when you put a load ,i.e. above 2000 RPM, the engine is starved for gasoline.

 

I replaced fuel filter, washed tank out, let it dry inspected it for any dirt, completely cleaned out. I tested my throttle position sensor it tested fine. Thank you

 

P0122 tps circuit low.......throttle position sensor...bought one havnt put it in yet and p1875. Transfer case control module....havnt bought one yet....those are the codes....thank you too all who responed..ill post the outcome when i put sensor in..

 

Put new tps in today...still doin it...hit 2000 rpms and drops to 500 again. ....

 

I found that if i manually shift the gears it dosent do it....which leads me to believe its one of the shift solenoids in the transmission...i will be replacing both of them and the tcc sensor... ill post the outcome after i put them in....

 

BcZ, I once had a shift problem with my 1994 Impala SS with the 4L60E trans not shifting properly. It was shifting in only two of the four speeds. I read it was a shift sol. --can't remember which one--and dropped the pan and replaced it in my driveway. It solved that shift problem. I have read since that many of the 4L60E problems can be fixed by replacing the entire valve body which has all the solenoids in it. Anyway, I hope that solves your problem.

 

BcZombie, did the tccm fix your drop in rpm issue? thanks