well i recently had bad luck with my car. i did my tune up and i been having weak reaction. i recently changed my plugs , wires cap and rotor, air filters and fuel filter because i thought the car needed a tune up. but the car runs the same its missing poweror something. on overdrive or regular drive the car wont pick up speed. over 3,500 rpm it picks up great as i suppose to. under 3,500 it hesitates and wont go no where. what can this be?i have an idead that its the egr because it seems like its leaking but what can it be it?

 

Have you scanned the computer? If not, that might be the better thing to do and see what is really going on.

 

I am having the same problem as you, let me know if you find anything!

 

Check your Coil with a multimeter.. make sure all your wires are not getting grounded somewhere..

check the EGR solenoid, follow the vacuum tube from the EGR to the solenoid. also pull the EGR and make sure there is not a huge carbon build up on it. you can use some Gumout or carb cleaner on it, also check the solenoid and make sure the passeges are clear.


forgot to also ask if you have an adjustable fuel pressure regulator. check the pressure with a gauge at idle, if you can, get a friend to rev it and check out what it does.

if none of these things work, start checking voltage on the fuel injectors(you can do this without removing them)

get a digital multimeter from a part store, they are usually 12$.

 

I think I would save removing and checking/cleaning hte EGR for last, since it takes a lot of effort to even gain access to it:



There are a few other things to do/check as part of your tune up:

• Inspect all vacuum hoses;
• Clean the PCV valve or replace it;
• Clean the throttle body and throttle valves;
• Clean the IAC and its air passages;
• Check/set the minimum air position;
• Check/set the TPS voltage;
• Test teh ignition coil as described, although if the engine will run and make power at 3,500 RPM, chances are teh coil and ignition system are fine;
• Check/set the base timing;
• Test standing and running fuel pressures;
• Check the O² sensor function;
• Scan the ECM for error codes. After doing the above procedures, you should generate a couple of error codes in addition to others that may have been already present;
• Verify that the air intake ductwork is sealed and that the ducts and hoses are not cracked, split, or damaged (there was a TSB on this problem);
• Replace teh filter on the underside of the EVAP canister.

Soemthing in that list should solve some of the problems or help reveal them.

 

i had the same problem on my 91 z28 i had no power so i put in a new knock sensor it it now has all kinds of power

 

so it hsould be the egr valve? cuz when i did my plugs i found a deposit of oil on my plugs it looks bad!! and its missin power!!

 

i agree w/ 91 z28 check you knock sensor! hell even just unplug it and see what it does.

 

i changed the egr valve and i feel a diference way better but it doesnt feel like it did before. now im goin to change the iac and tps

 

I tried to caution you not to jump on the EGR so quickly.

Go back and read my previous post. I mentioned that you should clean the IAC and its air passages. Simply replacing the IAC may be a waste of time and money. Since you need to remove it either way, you might as well clean and relubricate the existing IAC.

And before you simply replace the TPS, test the existing one. You'll need a DVM to set the new TPS anyway, so you might as well just test the TPS for intermittent output and correct idle output voltage.

You can add to that prior list "Check compression or cylinder leakage".

 

what baout a plugged cat? i was having the same problems for a while except i couldent get past 2000rpm

 

question, how can you tell if you have a bad knock sensor?? I am having a problem with my tpi and am getting NOWHERE and is there a way to TEST the IAC and TPS, on my computer the TPS volts are .56?? If you wanna help my thread thank you

 

where is your knock sensor and egr valves located. i am also having this problem with mine

 

this is what I had wrong ...when I shared the same symtoms as yours. It wouldnt idle. BU tif I kep tthe revas up it was okay ..... but it fealt all spoongy on the low end ...not very responsive. It was a vacuume line I had not pu on the TB