shudder during acceleration, hot days

[bojaz01]

i have a 99 expy xlt, purchased in oct. of 2011. Everything worked fine at first. When it starting getting cold out the engine would shudder on acceloration, then smooth out. Had codes ran saying vac leak. Egr was replaced but now it shudders when its hot out. I had it scanned again this time it said miss-firing on 1 and 2 cyclinders. I also had a friend look at it it and listen to it and hes saying its the tps. The questio i have is, would a tps going bad cause missfiring in 2 cylinders? Why does it seem to be effected by air temp? Im on an extremely tight budget. During just cruising it does just fine, shifts smooth too.....plus there is a pinging sound that comes from underneath, but just that, a pinging sound, no surge or shudder....I would greatly appreciate any help or advice on this subject.

 

[2000ttownexpy]

i'm not sure about the pinging sound, but the shudder sounds like COPs... if you are getting codes, swap COPs from a good cylinder to one of the bad ones clear your codes and see if new codes follow the bad COP... if so, replace it.

 

[catmaster25]

not sure

I had about $700 dollars worth of work done to clear my check engine light, but it still didn't clear. I was pissed at my mechanic, then I went to the junkyard for some running boards that I liked and saw a air intake hanging out from under the hood, so I cut it off and switched out my MAFS... Took my SUV back to have codes cleared once more and sure enough the check engine light has been off for 3 months now. Although my transmission seems like it has trouble shifting into 2nd. I don't know why

 

[bojaz01]

thanks forthe input....after havingmy dr caliper freeze up on me i i fugured what the heck, it aint running now, it cant get worse so i replaced the caliper, rotor,and pads and feeling bold changed plugs and wires, and one coil (edis system).....Made a hell of a diff. i have power again. Found a vac leak in rubber/metal hose that goes from a ********* drum looking thing to the back of my intake, whick also has a bracket that attaches near the egr valve, anyway, the bracket came lose leaving 2 holes, to temperarily remedy i used i high heat duct tape to seal the holes and havent had any other problems except the chack engine light came back on....ill have the codes cleared after i replace a couple of the vac lines......Thanks again for the input