Engine Performance problem
1997 Chevy Blazer 6 cyl Four Wheel Drive Automatic 105000 miles
engine starts and idles fine. When I apply power the engine stumbles and stalls at about 1/3 throttle. Installed new fuel pump (twice), fuel filter, pressure regulator (2000 miles ago). No codes show up. Removed cat converter, no change. Fuel pressure shows 53lb at idle and increases to 60lb when throttle is slowly increased until engine sputters and dies at about 1/3 throttle.
Possible TPS Throttle position Sensor located on throttle body. It sends info to PCM as to throttle angle. If it is defective the PCM when it hits 1/3 make think it is at idle and back off fuel and timming advance. There is no adjustment or repair for a TPS and you would need to have engine scaned to confirm if it is defective. What happens if you nail it? If stumble only occurs at1/3 throttle then TPS maybe the culprit. Let me know
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September, 9, 2008 AT 12:59 PM
Wouldn't faulty TBS throw a code?
September, 9, 2008 AT 1:00 PM
Wouldn't a faulty TPS throw a code?
September, 9, 2008 AT 1:05 PM
Not as long as ECM is getting input signal, thst is why you need it on a scanner
September, 14, 2008 AT 1:55 PM
TPS checks out using a digital volt meter, with 0.6 volts at idle to 4.8 at full throttle. Any suggestions as to where to look? Thanx
September, 23, 2008 AT 8:44 AM
Could be your Mass Air Flow sensor. Try cleaning it with a Q-Tip because I had the same problem!
October, 21, 2008 AT 9:46 PM
CHECK THE BUTTERFLY IN YOUR THROTTLE BODY, MAKE SURE YOU DONT HAVE CARBON BUILD UP, USE THROTTLE BODY CLEANER IF SO, CHECK THE VACCUM LINES ON THE CAR ALSO, SPRAY THE CLEANER ON THE LINES IF YOU HEAR A DIFFERENCE IN THE IDLE THEN YOU KNOW YOU HAVE A LEAK, BUT CHECK INSIDE THE THROTTLE BODY FIRST. GOOD LUCK!