inconsistant throttle response.
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,672
Likes: 8
From: Sumter South Carolina
inconsistant throttle response.
'89 L98 with high flow manifold, runners, and ported plenum.
Problem is intermittent and throws no codes. First the car hickups at low rp when warming up, sometimes it feels like hitting bump and happens like every 3 or 4 seconds. Only at low throttle conditions.
Next is if car is warmed up to temp, and then stomp foot to floor most of the time its ok, I feel like im at 90% power. Then every so often if feels as if a rev limiter kicks in and it sputters, shutters, and coughs. I immediatly lift off the throttle and then ease back on it and its fine. I find it happens more if right after I shift, I stomp it instead of easing back on the throttle.
I am thinking the TPS... but I would think that would throw a code. Maybe some ignition component? I really don't want to chase ghosts but seeing how it has almost 150k on the clock, I bet the TPS is about to go anyway.
Problem is intermittent and throws no codes. First the car hickups at low rp when warming up, sometimes it feels like hitting bump and happens like every 3 or 4 seconds. Only at low throttle conditions.
Next is if car is warmed up to temp, and then stomp foot to floor most of the time its ok, I feel like im at 90% power. Then every so often if feels as if a rev limiter kicks in and it sputters, shutters, and coughs. I immediatly lift off the throttle and then ease back on it and its fine. I find it happens more if right after I shift, I stomp it instead of easing back on the throttle.
I am thinking the TPS... but I would think that would throw a code. Maybe some ignition component? I really don't want to chase ghosts but seeing how it has almost 150k on the clock, I bet the TPS is about to go anyway.
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
If you lift and roll back in ok fixes it then it is almost always lack of fuel for whatever reason. Could be fuel psi for a bunch of reasons or bad maf that did not send enough fuel to the engine.
Team Owner
Joined: Jul 2004
Posts: 28,499
Likes: 3,298
From: Hartford WI
Hook up a fuel pressure gauge to the schraeder valve in the fuel rail and see what you get. Drive with it taped to the windshield and see what it does too.
Hook up scanner and see what you get with the engine off as far as TPS voltage goes. As you depress the pedal it should increase STEADILY AND SMOOTHLY.
Hook up scanner and see what you get with the engine off as far as TPS voltage goes. As you depress the pedal it should increase STEADILY AND SMOOTHLY.
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,672
Likes: 8
From: Sumter South Carolina
Ok, didn't cross my mind that fuel would be a problem since it is periodic but it makes sense. Its a new pump and pressure reg, might be bad filter or the regulator not getting it up where it needs to be. Thanks for the feedback.
