I have been wondering about the lackluster throttle response of my '91 for awhile, so I'll ask...

It seems that it lags for about 1/2 to 3/4 second before moving after I stomp the throttle from a standstill. Also the truck seems like it is stopped up somehow when accelerating on the road.

I have added a K&N FIPK. No other mods related to engine.

Is this typical of the '91ish trucks with 5.0 and auto, or is there something I should check/replace? What mods will effectively reduce or (better) eliminate the lag and lackluster performance once the truck is moving? I think it boils down to an airflow problem.

Truck has 98,500 miles on it.

Thanks,
-Mike

 

Advancing the timing helped my truck out with that problem- its a '94 with a 302 HO engine in it with a K&N FIPK-also getting the exhaust done helped in a big way-its just about eliminated the hesitation all together-the timing was at about 12 degrees but I moved it up to 15 and it still runs good but I may back it off to 14 as per the reccomendations of several here

Good luck with it- I know its frustrating as hell

 

Hey Mike. I'm sure you'll get some more responses to this, and I know you're familiar with the battery disconnect to reset the computer. I usually drive my truck just to and from work, about 35 miles daily, with most of it being highway. It is usually when I play taxi for my step daughters during the weeknights occasionally that my truck takes on that sluggish feeling(after about 3 weeks of it). Mine is a clutch, but I also start to notice that sluggish takeoff, have to wind the crap out of it and like you said, when out on the highway, it is doggy with no power. When playing taxi, it idles alot, stop and go traffic, short trips, etc.. I have always reset the computer for any mechanically changes, like plugs, new filter, etc.. I have started to reset the computer to see if that would help, and sure enough, it gets its' old zip back. We know that the computer relearns our driving habits with the reset, but I wonder after running the truck awhile if the computer readjusts to another "setting", because of the long idling, the short trips, stop & go traffic. I can always feel it coming on, and even the tone of my exhaust will change. But it helps mine to reset it. I don't know your driving habits and know you haul alot with your truck. Might be the air, but I would lean towards ignition. I know at one time Summit Racing offered a high performance Ford Truck coil, but haven't seen it lately. Anyway, the resets work for me. My 2 cents worth! (Yes, there is a world of ignition systems out there for our trucks too)

 

I tried the Jacobs setup several months ago with no results whatsoever. Couldn't tell a difference in mileage, but did not have the system long enough to tell. I have heard mostly good things about the MSD--a little gun shy about trying any more ignition mods... Might think about trying it again, though... not sure how much it'll help the lag from a stop.

 

Mike,

Depends on what you are considering the hesitation. If I remember correctly your truck has a tall gear. Even with mods the 302 isn't a low end torque monster, as the converter will stall before the engine is really into the torque curve.

As for mods go with what you are comfortable with. I know of your experience with the ignition, but on my '95 I still consider it the single best mod I have done.

Short of anything expensive, the timing adjustment is a free mod. My '95 seems to tolerate about 14 degrees BTDC as a maximum on regular gas. Running mid grade or premium I can get away with more, but not enough to justify the gas price difference IMO.

As for where different mods and adjustments helped with my truck....

Ignition and timing changes helped the low end most.

Intake helped more in the higher rev ranges but some down at lower revs.

Pulleys and exhaust seemed to help at just about all RPMs, but not much off idle.

As for order I did the exhaust last this time around. The truck responded well with the stocker but the exhaust helped open it up some more. Overall I would say the intake and pulley combo helped more and they were cheaper as well. The only thing that really seemed to strengthen off idle torque was the ignition, big gaps, and the timing advance.

What I really want is a good aftermarket torque converter, but they are rather pricey.... the $700 range.

 

Mike,
Try opening up the exhaust. I went with some JBA shorties and a Gibson cat-back on my 1993 (5.0, E4OD) back in '95 and couldn't believe the difference in throttle response. It's running with 3.55's in the back, if I remember correctly. Recently, I had to put the stock manifolds back on because I found a crack in my headers. Big difference.