well i just finished my Dohc swap, and everything seems good. but when i driving it, it doesn't really "cruise" as long as im accelerating its fine but if i let off the gas then push the gas again it kinda hesitates for a second then sort of jerks/ kicks i guess you could call it. then it takes off really quick.

also if i have it just idling and i rev it say to 1500rpms it will rev up then go back down then kinda rev by itself a tiny bit, probably back up to 1200rpms.

if it matters, i did put a mopar performance cmputer in it, so i had to mix less then a half a tank od 87octane and filled it the rest the way up with 93 octane.


do you think it could be related to a vacuum leak or something, i rechecked all hoses several times and cant find anything.

or maybe another possibilty could be my throttle cable or something?


any help would be great. thanks.

 

Sounds like a vacuum problem. Maybe a TPS.

 

alright ill check it do you think maybe the gas has anything to do with it since it is a wierd mixture of the two types. also the 87octane gas sat in the cold for about 3 months to. if that had anything to do with it.

also if it was the TPS wouldn't i be getting a code?

 

Sensors can go bad w/o throwing a code.

Could be some bad gas.

 

Doubt that it is the fuel, I have '98 DOHC with MOPAR Performance Computer and I have run several tanks of 87 AKI octane rating fuelv and I have no issues with it acceleration and it has never had a pre-ignition problem with the regular grade fuel.

 

^^^Keep running 87 octane and you will start to develop a pinging problem, if you haven't already started to hurt the engine.

I don't understand why people run the Mopar PCM and then cheap out on the gas. With 87 octane in the system, you don't get the performance out of the PCM.

 

i did the swap myself too. no problems however. but i would say it does sound like a vacuum leak. check for a leak around the tb because if you didn't get a new gasket that could be your prob. i had trouble sealing the tb goin from the plastic intake manifold on the sohc to the aluminum one on the dohc without gettin a new gasket. also check the iat sensor that coulda gone bad. any check engine lights? try usin the stock computer to finish up that tank of gas and maybe for one more tank and see if you throw a code. that is if you have a 97-99 stock dohc comp.

 

also the stock comp. will throw more codes than the mopar will. i eliminated my egr and evap purge solenoid system and the mopar comp for me never threw a code. but my stock one will throw an evap code a o2 sensor code and egr flow code very quickly and my mopar comp wont throw any of those. the only codes i've got out of the mopar comp is misfire codes and fan sensor relay

 

i have looked all over town for a new Tps sensor and cannot find the right one.
the one i need is where the harness plugs into the sensor horizontally. and it also has round plugs.
all the ones around here and the ones the plug in from the top and have flat plugs.

i have trade autozone, advanced, napa, car quest.

maybe the dealer?

any body know where to get it at?

 

i got my dohc tps at autozone i had to drive down to the hub to get it cuz no one stocks that part. if nothing else then maybe try a junkyard. or use the haynes manual to see how to test if its bad with an ohm meter cuz mine was 77 dollars