I have a 1991 f150 5.0 . When I'm driving at a constant speed . While my throttle is applied very lightly my truck jerks and surges. If I step on the gas and accelerate it runs smooth but if I'm tryi.g to hold speed. It runs really rough . Any thoughts would be helpfull. I'm thinking throttle position sensor. But maybe something easier . Also my truck started today having a Hella of .a time idling down after start up. Stays at 2000 rpm usually it takes a minute to warm up. I don't know. Thanks a bunch. Have had a full tune up less then 2000 miles ago. Including fuel filters.so I know the plugs are gapped and everything is good in that department

 

First pull codes to see what if anything has been flagged.

If it's not sensor related your problem could be related to a vacuum leak, a stuck or faulty EGR system, or a broken/leaking thermactor(air injection) system

 

my 92 was doing that and i changed my tps and fuel filter and it went away but not shure witch one was the fix,

 

Mine's doing something very similar except for your idle problems.

Staying tuned to see what if any codes come up, I had no codes myself.

 

Unfourtunatly no codes being thrown no check engine light. I think Its the tps. I hope. Gets annoying on I5 jerking around

 

Same situation but it only happens for me on the freeway going over 65 steadily. Have done the sixlitre tune-up and it didn't fix it. Got the fuel filter and I'll post if it fixes it

 

Def not fuel filter. yours could be. I have new fuel filters and the full pop deal tune up. Still does it. So stupid the intake manifold has to come off to change that stupid sensor. Just like when my distributor sensor went out. Have to pull the damn thing out. Makes me.miss having a carb. Lol. But my gas milage is 15 instead of 8_9

 

you said no CEL did you actually check the codes or did you just think oh no engine light means no codes..? just double checking.. even if the engine light isn't on doesn't mean it hasn't stored some codes away..

 

I don't have a code reader.. and I'm not taking it in to get codes read. If anyone around Everett Washington has one ans will do it . I'll Give em 30 bucks and a 6 pack of.their choice. Lol. If not.I'm just going to replace.tps

 

^^^^ X2 ^^^^

 

It's been ongoing I've had a tps in mt glove box for almost a year. The check engine light did come on one time for 20 seconds could that store a code

 

Yes.............

 

Ok wow. Crazy. Still new to computer. Maybe ill get her chexked out

 

any time the check engine light comes on.. it stores the code it threw.. if that lights comes on you should figure out what it is.. MOST PLACES will check your codes for free.. no need to spend 30$ and a 6 pack.. most auto part stores will do it for free.. your local garage may not because they are mean like that... i would highly recommend you checking your codes before slapping parts on you don't actually need.. and when you find out what code it is throwing figure out why it is throwing it.. people always love to just replace whatever threw the code and think they are good to go.. but more often then not a few months later and you are in the same situation.. i understand you said you aren't going to take it to have codes read but we can't help you if we don't know whats wrong with it..

 

The truck also has delays on power. And hard down shift drom overdrive to drive.